Genealogy histories show Toa and Tapairu had four daughters. Toa married each of these daughters in an attempt to produce a male child. Finally, a union with a grand-daughter produced a son, and the youngest daughter produced another boy. Parent-child marriages appear to have been banned after that. Rakahanga was isolated from wars and infectious diseases, and the population grew rapidly. By the sixth generation, the community had split into two tribes under separate arikis (chiefs) and a "tuha whenua" (Land Distributor) was appointed to arbitrate disputes. By the ninth generation there were four tribal groups, still based around two ariki.