Batak societies are patriarchal organized along clans known as Marga. The Toba Batak believe that they originate from one ancestor "Si Raja Batak", with all Margas, descended from him. A family tree that defines the father-son relationship among Batak people is called tarombo. Toba Batak are known traditionally for their weaving, wood carving and especially ornate stone tombs. Their burial and marriage traditions are very rich and complex. The burial tradition includes a ceremony in which the bones of one's ancestors are reinterred several years after death. This secondary burial is known among the Toba Batak as (mangongkal holi).
