The Nambudiri's grip on land was maintained through the practice of strict primogeniture and patrilineal inheritance. Despite their younger members having hypergamous relationships with Nairs, whose caste traditions were matrilineal, Nambudiri families remained aloof from general society. Although the historian E. K. Pillai has claimed that the Nambudiris from the 1100s enforced matrilineal polyandry on the previously patrilineal communities of the area, sociologist Randall Collins thinks it is unlikely that such a change could be imposed and says that "more probably it was the result of a process of marriage politics spread by emulation in the decentralised situation of status competition." Some other scholars believe that the matrilineal customs predate the period entirely and cite the queens of the Pandyan dynasty as evidence for this.