Tu Tapu

Tu Tapu was the birth son of Maonga and Pou Teo and was adopted by Maonga's brother, Pou te Vanangaroa ki Iva, high chief of Tahiti and the Marquesas. Pou had two born-to sons and another adopted son (Tangiia Nui). Pou divided his territory between the four men, with Tu Tapu being given the Marquesas.

Tu Tapu and Tangiia Nui fell out over the possession of a bathing pool and ceremonial regalia, which eventually escalated into full-scale war, lasting for many years, stretching across the South Pacific and causing the deaths of many warriors and civilians. It did not end until Tu Tapu had pursued Tangiia Nui to Rarotonga in the Cook Islands, where he had settled peacefully.

In the end, Tangiia Nui killed his adoptive brother in single combat. The body, after its tapu had been removed, was cooked and eaten.

The legends of the war between these two adoptive bothers comprise one of the principal primary sources for the history of early Polynesian migration, and also one of the main pieces of evidence of their legendary navigational skills. But it is now accepted that while the main characters and outline of the history are quite likely based on real people, the details of the voyages are unlikely to be historical.

References

MacCauley, J.J. Te Ato o Ikurangi; The Shadow of Ikurangi. ([Avarua]: Cook Islands Library and Museum Society, n.d.) (Cook Islands Library and Museum Society Bulletins; no. 2)
Te Ariki Tara Are, and Smith, S. Percy Smith "History and Traditions of Rarotonga," Journal of the Polynesian Society, 28 (1919) pp. 183-97; 29 (1920), pp. 11-16, 45-65
Kawaharada, Dennis. "1992 No Na Mamo: Sail to Rarotonga." Available at: http://leahi.kcc.hawaii.edu/org/pvs/1992/rarotonga.html