THE CULTURED ISLAM: THE BOUNDARY OF ISLAMIC IDENTITY BETWEEN THE MINANGKABAU AND MANDAILING ETHNICS

The relationship between Islam and culture was compatible and not antonym. Islam was a dynamic product and a long-term process of giving and receiving its people’s dynamics and social interaction. The contradiction between the ideal demands of religion and the demands of tradition and society’s social reality was a crucial problem faced by any religion in the world, but adjustments to social reality always occurred. The Islamic society in the Minangkabau border area was a cultural community that had and continued to confirm genuinely and became accommodative openness in resolving the contradictions of adat and Islam which were in principle very apparent in their cultural systems. Through ethnographic research, this article revealed that conflict and contradictions between the normative concepts of Islam and adat (custom) always occurred in societies of Minangkabau and Mandailing ethnics, especially related to marriage, kinship, inheritance system, and communal property ownership. However, the process always ran elegantly and attractively through the dialectics and the dynamics of the people. Thus, Islam was culturally acculturated with Minangkabau and Mandailing, and formed a distinctive cultural Islamic identity in the border area. Relasi Islam dengan kebudayaan adalah sesuatu yang selaras dan bukan antonim. Islam adalah produk dinamis dan proses dalam jangka panjang, yang saling memberi dan menerima dalam dinamika dan interaksi sosial masyarakatnya. Kontradiksi antara tuntutan ideal agama dan tuntutan tradisi serta realitas sosial masyarakat merupakan persoalan krusial yang dihadapi agama apapun 224 The Cultured Islam: The Boundary of Islamic Identity el Harakah Vol. 22 No. 2 Tahun 2020 el Harakah Vol. 22 No. 2 Tahun 2020 di dunia, namun penyesuaian realitas sosial selalu terjadi. Masyarakat Islam di daerah perbatasan Minangkabau adalah komunitas budaya yang telah dan terus melakukan konfirmitas secara genuine serta akomodatif terbuka dalam menyelesaikan kontradiksi adat dan Islam yang secara prinsip sangat kentara dalam sistem budaya mereka. Melalui penelitian etnografi, artikel ini mengungkap bahwa konflik dan pertentangan antara konsep normatif Islam dengan adat selalu terjadi dalam masyarakat etnik Minangkabau dan Mandailing, terutama masalah perkawinan, kekerabatan, sistem kewarisan dan kepemilikan harta komunal. Namun proses itu selalu berjalan secara elegan dan atraktif melalui dialektika dan dinamika masyarakatnya. Sehingga, Islam secara kultur berakulturasi dengan budaya Minangkabau dan Mandailing dan membentuk identitas Islam kultur yang khas di daerah perbatasan.


Introduction
Islam developed in Minangkabau had a unique dialectic between customs and religion. This dialectic is expressed in detail in oral histories, sayings, and folklore. The dialectical relationship between religion and tradition in Minangkabau varied and colored its people's history and dynamics. Thus, this ethnic has captivated the imagination of foreign observers since the beginning of the 19 th century. The earliest is Bousquet and Van Ronkel, who regarded the Minangkabau case as "a striking paradox in Islamic sociology" (Abdullah, 1966). Another one states that Minangkabau's identity is strong and ambivalent with various layers and full of contradictions (Benda, 2007).
The contradiction of the demands in religion and tradition, also the reality in society are crucial issues faced by any religion in the world. The adjustment of social reality with religious doctrine is started with the minimum requirements of the two ideal demands so that the Islamization process in Minangkabau is emphasized more on the recognition of basic values and general principles. As time goes by, Minangkabau developed self-understanding in cultural identity implying a reconciliation that is constantly shifting and not always following the normative order.
Principally, the concept of conflict was merely recognized and developed in Minangkabau's social system. The dynamics and contradictions always struggled in various dialectical relationships between cultural values and external elements in society's long history. This dialectic and change connoted in a cultural philosophical connotation which stated that diversity and uniformity were integrated into the living and thinking systems that symbolize the Minangkabau Islamic identity (Klopfer, 1994). Thus, the antithesis between adat (custom) and Islam produced a synthesis that then became the specific characteristic of the Minangkabau Islamic culture.
The unique phenomenon of Islamic culture in religious dialectic with cultural dynamics was found in the Minangkabau border area. The border area, which was categorized as a rantau (the coastal) area, was inhabited by the Minangkabau ethnic as the original residents and other groups such as Mandailing, Malay, and Toba Batak as migrants. From the aforementioned place, Islam began to spread in Minangkabau. Historically, Islamic teachings had entered this multi-ethnic region since the 7 th century AD through the east and west coast routes brought by Aceh and Gujarat Indian merchants. Furthermore, Islam's spread was perfected by the vibrant and popular Paderi Movement in this border area in the 17 th century (Dobbin, 1983). According to Pelly, this historical evidence confirmed that Minangkabau and other ethnics such as Mandailing and Malays had long embraced Islam. Specifically, in the Minangkabau and Mandailing, Islam and adat had long interacted and supported each other in the form of expressions of the ethnic identity of the two groups. For both ethnic groups, cultural and religious boundaries were isometric (Pelly, 1983).
Many researchers are interested in studying these two ethnics, Minangkabau and Mandailing (Tanjung et al., 2016). One study states that both ethnics always fight for their identity from the colonial period to the construction of social dynamics and interacting with the Batak ethnic that is the majority in North Sumatra (Lubis, 2001). It is then concluded that Mandailing is always within political and cultural boundaries (Lubis, 2005). In another study, the history of trade on Sumatra's island by the Batak ethnic is highlighted. Here is how Mandailing is dominated by what they called the Batak ethnicization effort because they claimed that one of the Batak ethnic was included in Mandailing (Andaya, 2002).
Meanwhile, some studies also discuss it from many angles ( Von Benda-Beckmann & Von Benda-Beckmann, 2010;Von Benda-Beckmann & Von Benda-Beckmann, 2012). One study examines how Minangkabau ethnic experienced social-political dynamics changes since the reformation era, especially related to natural resources and communal land (Biezevelt, 2010 (Simon, 2014) and their efforts to 'realize human values' (Simon, 2009). Studies also brought up Minangkabau's unique matrilineal system's dynamics from ancient times to the present (Hadler, 2008;Bonate, 2017). The contemporary dynamics of the Minangkabau in the digital age is also reviewed and becomes the spotlight. This ethnic is increasingly changing and constructed in the virtual era called global virtual (Franzia, Piliang, & Saidi, 2015;Franzia, 2017).
However, few studies of Islamic identity focus on this border area. The existing ones are only in some parts of research on Minangkabau and Mandailing. For example, when discussing the history of the area and its social dynamics, the former researcher also wrote about Muslim and matriakat (Hadler, 2008) . When studying about Mandailing, the researcher concerns more on the reality and social dynamics of this ethnic especially after the Paderi war. He never mentions the Minangkabau border community dynamics even though Tuangku Rao and Tuanku Tambusai were Padri figures from the Rao area (Lubis, 2005). These previous studies generally focus on the change of both ethnics' identity inside the community, and neglecting their outside communities.
This recent study gives a new nuance to the research of Islamic identity which has been done a lot. It turns out that Islamic identity was not fixed. It changes and can be constructed in the dynamic and process of social interaction. Here, the Islamic identity interacts and accommodates two principally different cultures but equal in religion perspective. Islamic societies has been accommodating to resolve the contradictions of adat and Islamic teachings which are principally very evident in a cultural system.
Based on the aforementioned problem, this article discusses how to draw the borderline of Islamic identity in the interaction and struggle between the Minangkabau and Mandailing cultures in the northern border area of West Sumatra, especially the Rao area which is known as the center of the Paderi movement with its famous figure Tuanku Rao. The religious and adat dialectics in this area reflect continuous dialogue. It always creates a consensus of cultural adaptation, synthesis, and acculturation to create Minangkabau's border culture's Islamic identity.

Rao: The Frontier Area in Western and Local Historian Records
The territory of Rao frontier is found in the Encyclopedia van Nederlandsch-Indie quoted by AC Milner. Rau is a district in the north Lubuk Sikaping subdistrict in Sumatra's Westkust Residency and is bordered by Tapanuli. Rao consists of Nagaris Panti, Padang Gloegoer, Lansat Kadap (Kodok), Tandjoeng-Batoeng, Taroeng-taroeng, Padang Noenang, Loebok Lajang, Padang Mantinggi, Langoeng, and Kota Radja (Milner, 1978). Dutch literature explains that Rao is located behind Tapanuli, in the north side of Minangkabau, and has total number of 25.000 in the mid 19 th century. To date, since the reform era, the area of Penghulu Nan Basa XV has been divided and distributed into seven districts; Rao, North Rao, South Rao, Padang Gelugur District, Panti District, Mapat Tunggul District, and South of Mapat Tunggul (Erman, 2006).
In the political culture of Minangkabau region, there are striking differences between luhak/darek and rantau. The concept of rantau (coastal area) is compatible with "frontier" and "boundaries" terms in sociological and political approaches. The terms "frontier" and "boundary" have often been widely used interchangeably by geographers and others to describe political divisions. Since Gloria Anzaldua published Borderlands/La Frontera in 1987, the term "borderlands" has become a revisionary project's trademark. It has also shifted critical attention to the active role of place in the shaping of identity. Peter Taylor (1985) concluded that "frontiers" and "boundaries" have probably been the most popular topic in political geography and it is important to understand the reasons behind their enduring popularity.
The cultural differences between darek and rantau result in dialectical pattern differences and tension between adat and religion in each territory. When darek hold firmly to the adat principles, conflicts and tension with religion become more severe. On the other hand, the rantau community does not bindingly adopt and practice adat principles, so religion's conflict is not dreadful. Meanwhile, the people of Nagari in the border area do not fully absorb the classical civilization from the central Minangkabau hinterland.
Thus, when darek was unable to accept Islam during the Paderi war, this puritanical movement was more accepted in the border areas. In the rantau area, Minangkabau culture was not so strong since several ethnics lived in this border area (Graves, 2009). Graves adds that the Paderi war was alleged to spread puritanical Islam amid the strong Minangkabau adat influence. It shows its inability to establish itself in the four areas of darek. On the other hand, this movement's phenomenon developed rapidly and soon spread in the Minangkabau suburbs, the border area located around the northern hotspot and in the hilly villages in the northern Minangkabau area. The Paderi movement was infiltrated by the outsiders, the marginal, and the areas that were traditionally considered as the fringe of the Minangkabau civilization (Graves, 2009).
The Islamic identity limitation through religious dialectics and adat reflects continuous dialogue that it always creates new formats and approaches. This is where the consensus of cultural adaptation, synthesis, and acculturation occurred. Integrating adat and religion was difficult to realize, but it continues slowly in a long time. However, it does not mean that all dialectical processes which is in the ideal condition is over.

The Changes in Islamic Culture: An Islamic and Adat Dialectic in Minangkabau
Islamic dialectic and Minangkabau culture can be found in the marriage and kinship system and the inheritance system and communal property ownership. This will certainly bring up the style of Islam's borderline specific culture and indirectly becomes a borderline specific identity of Islam in Minangkabau.

The Marriage System of "Jujur Pinang Sabatang" in the Minangkabau Frontier Area
In the long history of interaction, the multi-ethnic community in this border area had complex problems and the marriage system's uniqueness compared to other regions in West Sumatra. Cross-ethnic interaction at this border has changed Islam's culture in the marriage system and engendered a new compromise culture. Minangkabau and Mandailing ethnics that have different cultures in their interaction process have led to an cultural assimilation such as "jujur pinang sabatang" as a model of cultural compromise that organized intermarriage between both groups. This tradition arises to bridge the differences in the Sumando marriage system (Minangkabau) which is matrilineal and the Jujuran marriage system (Mandailing) which is patrilineal. The matrilineal marriage system in Minangkabau (Bonate, 2017) in principle enriches and legitimates the Sharia of Islam regarding marriage. In the ideal level of Minangkabau culture, the husband or the father is not the descendant. The father is treated as a guest in the family who can give offspring so he is named Sumando or Urang Sumando, thus, the marriage system is called a sumando marriage. His rightful place is in his mother's descendant. The man in Minangkabau is the guardian (Mamak) of his lineage and protectors of his property. So he must refrain from taking his people's land, and cannot claim a portion of the land for him. In fact, he has no place in the house, because the cubicles (rooms) are only intended for the female family members In fact, to maintain the social stability and continuity of kinship, Minangkabau culture adds rules and conditions that are not determined in an Islamic marriage. The rules on inter-family marriages such as pulang ka anaak Mamak (marrying the child of the mother's brother) and pulang ka bako (marrying the child of the father's sister) and cross-ethnic marriage are the efforts to maintain the cultural structure. Another effort is the rules about pantang (forbidden) marriage such as the prohibition of marrying someone who is blood-aligned according to the line of a mother or marriage within one tribe, marrying someone divorced by a relative, marrying two women who are relatives and others (Iman & Mani, 2017). Even though there is no religion restriction, it is prohibited according to the adat because it will damage the system and social harmony. Therefore, the marriage culture of Minangkabau and the one ruled by religion are different. It is so that the kinship system and social stability of Minangkabau are well-maintained. After all, doesn't Islam regulate marriage to maintain a kinship system and avoid extinction?
Meanwhile, among Mandailing ethnic groups, for example, the forms of Jujur marriage system were found. Jujur means a replacement that comes from the word tuhor, tukun, tukar which in Indonesian means change, i.e. the position of the girl or wife in the sense of religious magic is replaced with an object (Amri et al., 2016). With a Jujur marriage system, there is a necessity for the women that have different clans from their husbands to move to the husbands' clans. To do so, the husbands must give the religious magic items so that the women will be released from their original clans and do some chores in the environment of husbands' families. Ter Haar argued in Lubis that Jujuran money or sinamot is an honor to the woman's family as an offering to give her daughter to the man (Lubis, n.d.). The payment is a magic requirement for releasing and transferring the offspring by not disturbing the cosmic and social balance (Situmorang, 2018). The payment of Jujuran money from the man's family to the women's family means that their future children will continue the husband's clan and they become the heirs of the husband's family.
Thus, adat Minangkabau and Mandailing differs regarding husband and wife's marriage position. Marriage in adat Minangkabau occurs exogamically with an uxorilocal sedentary system where the husband lives in the wife's family home. They live in an extended family atmosphere. Meanwhile, in the Mandailing community, if she has been paid with jujur money, a wife will change her status to her husband's family clan (Djurip, 2000).
To bridge it, a compromise came to explain the position of married men or women and their status if they lived in their husbands or wife's kinship. In the beginning, in Mandailing tradition, only the husband had to pay Jujuran money to his wife hoping that his family would later join the husband's clan. Thus, the compromise in the jujur pinang sabatang tradition was that a wife must also pay the Jujuran money to her husband to get him and live in her matrilineal family environment although the husband did not have to move to the wife's tribe or kinship. Initially in the Minangkabau tradition in Pasaman, this tradition was not known. This reciprocal tradition was known as the jujur pinang sabatang (Noviardi & Rozi, 2017).
The marriage culture with jujur pinang sabatang of Pasaman people was formed from the accumulation of the heterogeneity of the people who inhabited the area. The guidelines used in the implementation of marriage principally still carried out their respective adat and traditions. However, in certain cases, a compromise and assimilation of the two were taken. This depended on the "negotiation" between the families who did the marriage. For example in a wedding ceremony, the bride was a Minang and the groom was Mandailing. If the wedding party was held in a woman's house, the adat used was adat Minang and vice versa.
The interactions that lead to cross-ethnic marriages processed well. Various forms of marriage process occurred. The mixed marriages began to flourish in the 1960s between Javanese and other tribes namely Mandailing and Minangkabau. However, we could not decline that the intermarriage had ever occurred (Undri, 2008). Because of the social interaction that began smoothly with each other, the indigenous people had been able to accept other migrants and had been able to communicate well between them.
"As a result of mixed marriages in polyethnic societies, people believe that there are no ethnic differences anymore, useful for eliminating negative ethnic stereotypes against other ethnic groups, disgust, alienation, and perceiving others as uncivilized. As a result, mixed marriages engender a sense of brotherhood, unity, and togetherness between ethnic groups. While the negative impact, we will encounter various cases in the Pasaman area el Harakah Vol. 22 No. 2 Tahun 2020 as the impact of intermarriage. The child does not have a tribe or clan and the husband's position in the family. This often happens when the child has a father from Minangkabau and a mother from Mandailing. Finally, the child does not have a tribe and clan".
In fact, in this area, the marriage happened between cross-ethnic that had the same religion and belief and between cross-religion. The religious differences did not prevent Muslim youth or Catholic girls or vice versa to get married. Although they were somewhat difficult to take care of this marriage's legalization, according to Law No. 1 of 1974, the Civil Registry Office no longer can carry out this kind of marriage. However, based on interviews with the church party in Panti, Pasaman, the church accommodated their wishes by acknowledging the marriage and legitimating it even though one of the couples was not Christian or Catholic (Noviardi & Rozi, 2017). The result of cross-religion marriage was the formation of mixed families, in which family members embraced different religions. The differences in belief happened to the parents and their children who were given the freedom to choose one of their parents' religions.

The "Bilineal" Kinship System in the Minangkabau Frontier Area
The marriage problems have an impact on kinship relations. The kinship pattern of lineage used in Minangkabau is the mother's (matrilineal), although most of the people there are Islam which is patrilineal (father's lineage). According to Franz Benda Beckmann, the Minangkabau matrilineal kinship system might not cause much attention if the Minangkabau community did not firmly hold into the Islamic religion. One question that has always arisen in the Minangkabau study is how two systems, namely the matrilineal Minangkabau kinship system can work together with patrilineal Islamic law. This is not an odd thing because Islam and Minangkabau ethnic can coexist harmoniously to create genuine flexibility for both.
In the Minangkabau matrilineal lineage, the formation of descent groups and the heirlooms' inheritance are arranged according to the mother's lineage (Blackwood, 1994). Within each Nagari, the Minangkabau social structure consists of descent groups such as a tribe and its parts: payuang (the group which has one niniak), paruik (one grandmother), and mande (one mother). All of that is a kinship group originating from a single ancestor (matrilineal descent group) which is counted out of marriage ties el Harakah Vol. 22 No. 2 Tahun 2020 (Februhartanty et al., 2007). The awareness of group identity bounds the smallest group to the largest groups. Power in the tribe, payuang or paruik, is in Mamak's hands (mother's brother). Even the child's custody is in the mother's hands because the child is included in the mother's kinship group (Kahn, 1976).
On the other hand, the Mandailing community adheres to the patrilineal family system that is an adat community that regulates the flow of descent from the father's side (Amster, 1999). Automatically, the position of father or man in the adat community is higher than woman. The family name used by the Mandailing people is descended from his father's clan (Lubis & Khoo, 2003).
Islamic culture's cultural contact and accommodation about matrilineal and patrilineal kinship can be found in the border areas, especially on Minangkabau's western coast. In general, Syafri Sairin believed that the Minangkabau rantau areas are more accommodating and open in resolving adat and Islam contradictions. To bridge the controversy between matrilineal adat teachings and Islamic teachings' values, the community carried out genuine confirmation. It was agreed that a boy could receive an inheritance of adat titles such as Sidi, Bagindo, and Marah from his father's lineage, but the tribal membership of the boy remains based on the mother's lineage (Sairin, 2002). The regulation of inheritance of adat titles through the father's lineage is included in the category of bilineal in terms of cultural anthropology, which means that the tribal membership is on the mother's kinship. In contrast, the adat title is obtained from the father's lineage. The bilinear kinship system practice is also found in several cases concerning the kinship status of the offspring of the parents who marry across ethnic groups in this multi-ethnic and religious area. There is a kind of kinship identity negotiation. They have the right to choose and decide which ethnic they want to be part of. In principle, the standard rules in determining children's identity in marriage are they automatically become Minang if the mother is Minang; or become Mandailing if the father is Mandailing. This principle does not apply in the case of parents of crossethnic marriages in this border area. It turns out that ethnic identity can be chosen and negotiated. Parents can determine which ethnic the children will belong to. Otherwise, the child may choose which ethnic they want to be. Therefore, in this case, found many children from certain ethnic groups change their ethnicity to be "Minang", "Mandailing" and "Batak". Interestingly, this status transfer in their tradition is carried out in the feast tradition by inviting close relatives and close neighbors to establish an ethnic identity.
This case happens to Sarib Lubis, a Mandailing, originally a Minang because his mother was Minang. The additional name 'Lubis' in his last name is a gift from his father's family who asked Sarib to join their clan. His ethnic status transfer happened when Lubis was 13 years old after he graduated from elementary school. Sarib explained: "After graduating from elementary school, my father's family from Mandiling asked me to use the name Lubis behind my real name. Lubis is not an additional name like the addition of the father's name in our last name, but this has an ethnic consequence that someone has joined the Lubis clan. The father's family held a party and traditional ceremony as inauguration to indicate that I had moved from ethnic Minangkabau to Mandailing. Right now, my birth certificate, kindergarten, and elementary school diplomas are still using only my first name without 'Lubis' while in my identity card, the name Lubis is added. According to Wali Nagari (the leader of the village), I will have some problems when I want to get my passport for a pilgrimage to Mecca. It is because the differences between my name in identity cards and my name in the birth certificate and the diplomas." Therefore, the problem that arises in this ethnic status transfer is the issue of names that impact other identities such as identity cards, diplomas, and birth certificates. The name is a part of someone's identity which becomes the first and main symbol. The name can symbolize the status and the taste of culture. The personal name is an important element of someone's identity because the interactions will begin with names and then followed by other attributes.

The Inheritance System in the Minangkabau Frontier Area
The aristocratic control of the Minangkabau northern border area impacts the community's social culture, especially the modification of land ownership which is more concentrated on some private ownership based on certain contracts. These Minangkabau border communities do not adhere to the Minangkabau matrilineal pattern even though they claim their ancestors from the Minangkabau hinterland.
In the original Minangkabau adat system, everyone, both men and women, will receive an inheritance from their mother's family. Subsequently, principally a boy also gets a share, but he cannot pass it on to his child.
Thus if he dies, the treasure will return to the descendants according to the maternal line, namely the nephew. However, in the Minangkabau adat heritage, men have cultivation rights, while women have ownership rights (Blackwood, 1994). This principle, at a glance, is opposite to the patrilineal system of Islamic inheritance. The inheritance ownership can be owned by boys and girls with the largest portion owned by boys (Chadwick, 1991). Conflicts between adat and religion on the issue of inheritance have emerged with the entry of Islam. The debate about inheritance severely occurred at the beginning of the 20 th century in Minangkabau (Syarifuddin, 1984).
Fortunately, the reformist scholars sought a way out of the inheritance system's contradiction by categorizing property ownership in Minangkabau into two categories. First, high inheritance is the inheritance from several generations such as the land of paddy fields, passed down from niniak down to Mamak (uncle), from Mamak to nephew, and the next generation. Second, low inheritance is a property that has descended from one generation, which means that assets are received from someone who is from one of the adat people or another person (Syarifuddin, 1984). In addition to the two types of inheritance above, there is also personal inheritance. The property they obtained by themselves is called personal inheritance. The land and other wealth collected by individuals during their lives are also called personal inheritance (Graves, 2009). This personal inheritance and low inheritance can be legally divided using Islamic inheritance law. High inheritance such as land and houses cannot be inherited by people outside the mother's lineage family. Even this semisacred property cannot be sold or pawned unless for certain reasons that have been established by adat. According to his, the conflict between Islamic and adat inheritance law can be eliminated as long as all scholars base their decisions on fiqh that has been modified and consider the adat social culture (Hazairin, 1967).
On the other hand, the Mandailing community who adheres to the patrilineal kinship system, in their inheritance distribution, believes that those who get the inheritance are sons. In contrast, daughters get a share from their husband's parents. In other words, the women get inheritance through grants from both their extended family and her husband's family (Harahap et al., 2019). The distribution of inheritance for boys is also not arbitrary because the distribution of inheritance has a specificity, that is the youngest son or in Batak called Siapudan, and he gets a special inheritance (Nofiardi & Rozi, 2017). Furthermore, the inheritance system in adat Mandailing is very contrary to adat Minangkabau. If a marriage ends due to one of the parties' death and they have no children, the inheritance of a woman who dies will belong to her husband. If a man dies, the pauseang (jujuran money) will still belong to the woman, while the male family cannot claim sinamot (dowry) (Thomas, 1979). If the marriage has a child, the wife's inheritance belongs to her child and the husband's inheritance belongs to his wife and children. If the wife wants to remarry not with her husband's family member, the wife cannot take the pauseang, and the inheritance will still belong to her child. However, if a husband and a wife get divorced and the divorce results from a woman's mistake, there will be a shift in wealth. The woman's family must return sinamot and cannot get pauseang. On the contrary, if a man or husband is wrong, a man cannot sue for sinamot back and the pauseang must return to the woman (Lubis, n.d.).
Like the marriage and kinship system, the inheritance system in this border area also accommodates the Islamic inheritance system, the matrilineal Minangkabau culture, and the patrilineal Mandailing culture. In this border area, the distribution of inheritance is more likely to be distributed proportionally to boys and girls. The inheritance in immovable assets such as houses and unproductive land is intended and bequeathed to girls. Whereas the movable property and productive assets such as business land, factories, and vehicles are usually bequeathed to boys.
The proportional distribution of inheritance and designation is bridging between the adat Mandailing inheritance system which gives more for men and the Minangkabau inheritance system which gives more for women (Helfi, 2015). This is consistent with the result of an interview with Sarib, a young Rao from mixed descent and Rao community leader, about this inheritance as follow: "The inheritance distribution system, if one or both of our parents dies, is usually immediately divided following he proper propriety between men and women. Men who have a high responsibility for their families get movable and productive assets, while women also inherit from their families. This principle is widely used by the border communities where one of their parents is from another ethnic group besides Minangkabau." This "bauntuak" (designation) compromise inheritance system seems to refute the assumptions and public opinion which argues that this border are tends to apply the patrilineal system more prominently in the distribution and regulation of family ownership and inheritance. As a el Harakah Vol. 22 No. 2 Tahun 2020 multi-ethnic society that already has a mixed kinship, researchers such as Graves argued that the distribution of this inheritance was not as strict as in the Minangkabau hinterland. Generally, according to her, the property has become private property and is classified as a personal inheritance that can be divided using Islam law (Graves, 2009). Whereas in reality, there has been a compromise and adjustment of the Islamic inheritance system with both Minangkabau and Mandailing inheritance systems along with changes in ownership patterns and social changes that occur in society.

The Utilization of Communal Property System in the Minangkabau Frontier Area
The ownership of communal property also causes social problems in this Minangkabau border area. In the adat Minangkabau system, land assets originating from land clearing carried out by communal ancestors in the line of maternal kinship become the communal inheritance (Hamka, 1968). In principle, this communal property must not be traded, so it will not be used up. Instead, it will increase due to personal inheritance that can become communal property after two generations of their descendants are extinct (Beckmann, 1999). The ownership of communal property provides an opportunity for all members from one clan to cultivate the land. Consequently, each group member will obtain the right to cultivate the land. The importance of shared land ownership would maintain the group's integrity in matrilineal societies (Evers & Korff, 1992). However, Islam does not regulate communal property because in principle all properties in Islam are private property and will be shared and bequeathed to children after parents die and so on (Biezevelt, 2010).
The ownership of communal property in the Minangkabau border area is in the hands of the local aristocracy's adat kings. According to the tradition of the people in the border area, the king is a descendant of the young king who was sent Pagaruyung Kingdom (Graves, 2009). Rajo Rao in the Minangkabau border area consists of 15 Basa princes called Basa Nan XV that is ninik Mamak (adat leader) in the Rao Mapat Tunggul area. They consist of fifteen people in power over the area and tribal members in that area. The role of Rajo Rao becomes essential. Every inch of land in a rantau area is controlled and managed by the king (Erman, 2006) Even though ownership of this communal land was in the king's privacy right, the status of ownership of communal property remained a social problem in the northern border area of Minangkabau. This historically began with the Mandailing people's arrival from South Tapanuli by smuggling to the Minangkabau area. According to Undri, their arrival as migrants (urang datang), worried the Pasaman people as native residents (urang asa) because the native community feared that migrants would control the existing forest land. With the decreasing amount of land owned by family members due to forest clearing carried out by migrants for both plantation land and settlements, indigenous residents' economical capacity in supporting their family members also lessened. This phenomenon had occurred before independence. Based on 1930 data, the number of existing forests was 5,010 bau and after the migrants came to the area with forest opening activities, the forest area was reduced to 3,280 bau (Undri, 2009).
Undri noted that from 1930-1940 in the northern border of Minangkabau, there were some deviances in communal land management. First, the entry of migrants to the Rao Mapat Tunggul area by smuggling (clandestinely) without complying with the contract made was a form of action that was very contrary to the contents of the agreement. Second, it was about the religious issues adopted by the migrant population. Indigenous people felt being fooled because 46 of the population embraced Christian which was very contrary to their religion, Islam.
Nevertheless, along with the change of times, the communal land began to change its status. It became the communal land owned by limited people or became the private property. Datuk Rajo, one of Basa Nan XV explained: "The communal land in the Nagari controlled by Rajo is starting to decrease along with the land clearing for settlements and livelihoods. This land is the specific land in Rao which does not exist in other areas. This is because the kings sometimes give the land to the migrants or even sell it. It is an open secret that many communal lands are traded. When the communal land in a Nagari is handed over to a clan through certain terms and agreements, the land has become the clans. Even the land that is sold will become the private property." Based on the above phenomena, negotiations, and agreements with the community in the border area occurred and continued to be carried out to maintain harmony and strengthen the border identity. The community had common adat rules that governed land ownership and control. These provisions had been made traditionally and applied to every community, both for the native residents (urang asa) and for migrants (urang datang). For the migrants who wanted to get land, they had to go through several stages; first, to find the ninik mamak in the nagari by fulfilling the conditions of el Harakah Vol. 22 No. 2 Tahun 2020 being a nephew of one clan. Second, after getting a mamak and fulfilled the adat requirements, it was then faced by the local adat meeting to announce that the migrant had become the nephew of one of the datuk. Third, agreeing to comply with all applicable adat and nagari regulations. This was confirmed by interviews with traditional leaders who said: "The efforts of the traditional leaders, Rajo Rao, the head of Basa Nan XV in maintaining the existence of communal land and social stability are the adat consensus on the communal land in the nagari in the border area, especially Rao. Even some agreements with the local government prove that adat through its leaders still plays a role in the control of the communal land." Even under any circumstances, adat institutions continued to respond to any land issues through joint consensus to think out some solutions in solving all their social problems. Adat compromise in utilizing communal land was formulated in the form of ba mamak or looking for ninik mamak in the nagari by fulfilling its conditions as one clan's nephew. With certain terms and conditions, new members were entitled to get rights to the clan's funeral land and even get facilities to get lease rights to communal land for settlement and livelihood. The ba mamak system, which is almost like the Malakok tradition (looking for a family) in the Minangkabau culture in general, is a distinctive identity of the border community in maintaining their adat identity and the existence of their communal land. This system reinforces the Islamic identity in the principle of ukhuwah in maintaining a helpful relationship between indigenous residents and migrants. Therefore, the cultural compromise done by these border communities strengthens an Islamic identity that culturally respects migrant groups in one brotherhood.

Conclusion
Islam is the religion of the majority ethnic in the border area of Minangkabau, Rao region inhabited not only by indigenous Minangkabau ethnic but also migrant ethnic such as the Mandailing and Malay ethnic groups. There were conflicts and contradictions between Islam's normative concepts and adat, especially related to marriage, kinship, inheritance system, and communal property ownership. However, the process always runs elegantly and attractively in this multi-ethnic society. Dialectic and change always occur between Islam and the matrilineal Minangkabau ethnic culture and the patrilineal Mandailing ethnic culture. Thus, Islam is culturally acculturated with Minangkabau culture and other cultures, and forms a distinctive cultural Islamic identity in the border area.
Islam as a religion when dealing with social realities that have so complex problems will experience changes in accommodation, acculturation, and modification. For example, marriage, when Islam regulates marriage and inheritance systems, with the development and interaction between ethnic groups with different cultures and backgrounds, the problem is more complex. It is time for the role of ijtihad (efforts) and intelligent solutions in explaining how Islam responds to the times' problems. This phenomenon is also found in other adat issues such as kinship and communal land utilization.
Therefore, Islam is a cultured religion and becomes an inseparable part of community lives. Islam has been interpreted in various ways, it has even become a guideline or pattern for community behavior. Islam is something that has been integrated with the culture of society. Islam is no longer in the holy sky but has lived with humans with their humanity. In its history, Islam had made history in the Islamic caliphates which also were full of humanitarian problems. That was why the history of the caliphate was also not always ideal. There were bloodstains scattered as a result of the dominant desire in that power.
The vigorous Islam is when Islam becomes a cultural base. Because when Islam becomes the basis of power, there will be a process of dialectics ups and downs. Cultured Islam or Islamic culture is Islam that does not deny the community's culture and Islam as sacred teachings. The relationship between Islam and culture is compatible and not antonym. In the long run, Islam is a dynamic product giving and receiving in the frame of placing Islam as a cultural base.