Tribal groups formed in different ways. Originally people identified themselves with the waka (canoe) on which their founding ancestor arrived from Hawaiki. The earliest iwi (tribes) and hapū (clans or descent groups) formed as the descendants of waka groups expanded over succeeding generations.
Some of the tribes formed in this way trace descent from a single waka. For example, the Waikato tribes descend from the Tainui waka; tribes from the Rotorua lakes district and Lake Taupō are from the Te Arawa waka; and the Ngāti Kahungunu tribes between the Wairarapa and the south of Gisborne belong to the Tākitimu waka.
Other tribes descend from several canoes. For example, Ngāpuhi in Northland traces its origins to the Matawhaorua, Ngātokimatawhaorua and Mataatua canoes. Other tribes living in separate regions trace descent from the same canoe but have different accounts of that canoe’s history.
Iwi and hapū descended from the same canoe would sometimes act in opposition to each other. But if tribes from another waka region invaded their domain, the waka bond would be used to form an alliance against the intruders.
Reasons why new iwi and hapū formed
New groups also continuously split off as populations increased. Pressure on such resources as crops, forests, rivers, lakes and sea fisheries was an especially important factor causing larger hapū to break into smaller ones. New groups could also form through forced migration, defeat in war or other disagreements such as breaches of custom, loss of mana (status) or land, and family infighting.
Sometimes separate groups merged with each other to form new groups. Alternatively, very large and strong whānau (extended families) might develop into hapū in their own right. Recognition by other groups as a separate and new hapū was important. New sub-tribes were recognised if, for example, they had a leader with mana and skill in diplomacy, if they were able to strengthen the identity of the hapū by political marriages, or if they were known for their fighting prowess.