The "vata" village, referred to as "libata" in Kongo documents and by the Portuguese in the sixteenth century, served as Kongo's basic social unit after the family. "Nkuluntu", or mocolunto to the Portuguese, chiefs headed the villages. The one to two hundred citizens per village migrated about every ten years to accommodate soil exhaustion. Communal land-ownership and collective farms produced harvests divided by families according to the number of people per household. The nkuluntu received special premium from the harvest before the division.