The Maithil Brahmans of Bihar and the Bengali Brahmans of Bengal, two of the five great North Indian Brahman castes, had, as of the early nineteenth century, closely similar systems of ranked grades and hypergamously marrying lineages. In addition, fundamental concepts—of purity and pollution, of coded substance, of sattva, rajas, and tamas (Dumont 1970; Inden 1976; Davis 1983)—form a shared construction of reality for both groups of Hindus. Yet despite a common ideation and similar patterns of organization up to that point, the ‘Kulin system’ of Bengal virtually disappeared in the middle of the last century, while among the Brahmans to the east in Bihar, the system faltered during the same period, then corrected itself, grew more complex with greater refinements of rank than at any time in the past, and has survived into the present.