The descendants of the Polynesians who settled in New Zealand, arriving about 900 AD from central Polynesia, possibly from the Cook or Society Islands. The traditional Maori social organization consists of members of each tribe (iwi) who recognized a common ancestry and common allegiance to a chief or chiefs (ariki). The most important social groups were the hapuu (subtribe), the primary landholding group and the one within which marriage was preferred, and the extended family (whaanau).