How long ago the scattered islands of Oceania had been occupied and by whom has therefore been an enduring question. This is especially the case in the east Pacific where the majority of remote islands - landmasses that are 350 kilometres or more from another island - are found.

To navigators such as Captain James Cook, it was incredible that people in Tonga and Samoa spoke a language that was related to the languages used on islands thousands of kilometres away, in Rapa Nui (Easter Island), Aotearoa (New Zealand) and the Hawaiian Islands. The language similarity was unexpected, as it pointed to an ancient maritime migration covering more ocean than any other known to history.

Language comparison

West Polynesia and Triangle Polynesia language similarities

The region containing the shared language became known as 'Polynesia', a term popularised by the French explorer Dumont d'Urville in 1832. It was later subdivided into West Polynesia - Tonga, Samoa and 'Uvea mo Futuna (Wallis and Futuna islands) - and East Polynesia, containing all of the islands within the three archipelagos of the Hawaiian Islands - Rapa Nui - Aotearoa that outline Triangle Polynesia.

The corners of the Polynesian triangle are separated by 6,000 to 7,000 kilometres of ocean—similar to the distance from Brisbane to Tokyo. East Polynesia covers 36 million square kilometres of ocean, but within it the total amount of land is only 310,000 square kilometres—less than one per cent of the area. As Aotearoa comprises over 85 per cent of all land in East Polynesia, successful colonisation required remarkable canoe voyages, by people who were able to locate and settle small islands in a vast and mostly empty ocean.

The beginnings of Polynesian expansion lie in West Polynesia, which was settled 2,860 years ago during an earlier phase of oceanic expansion by pottery-making people of the Lapita culture. These people originated in the islands of South East Asia and migrated to islands around New Guinea before moving east into the Pacific as far as Tonga and Samoa. Around a thousand years ago, powerful chiefdoms developed in West Polynesia that had hereditary titles; the status of leaders was displayed mainly through architecture.

These complex societies maintained contact with one another using ocean-going canoes that were the property of chiefs, as they were expensive to construct and maintain. Competition and conflict among these groups may have led to the discovery of islands in East Polynesia, but unplanned voyages are perhaps just as likely, given the amount of canoe travel in West Polynesia. Another possibility, seen in a study of lake sediments, is that an extended period of drought 900–1,100 years ago led to social instability and voyages to find new lands to the east of Tonga and Samoa.

Whatever the reason, the discovery of new islands led to a rapid phase of migration that archaeologists have identified from the discovery of early sites in the Cook Islands, Society Islands and Marquesas Islands. Radiocarbon dating—a scientific method that measures the age-related number of carbon atoms in a sample—shows that wood charcoal from human fires in these island groups dates to 1,000–1,100 years ago. A second phase of movement, 700–800 years ago, then spread to the Hawaiian Islands, Rapa Nui and Aotearoa, which were harder to reach because of their remote position, small size and location in weather zones that were difficult to sail to due to prevailing winds and currents.

Oral history and navigation

In the oral history of Polynesia, these epic colonisation journeys were recorded in tales of ancestral voyages and famous captain chiefs such as Kupe (Aotearoa), Hotu Matu'a (Rapa Nui) and Kaha'i (Hawaii) who navigated canoes and named newly discovered lands. The homeland of East Polynesian colonists in these traditions is known as ‘Hawaiki’: this might refer to the island of Savai'i (in Samoa) in West Polynesia or to locations in the Cook Islands or Society Islands where voyages to the outer margins of East Polynesia began.

After reaching the limits of the Polynesian triangle, navigators might have ceased their expansion as they realised there could only be a small amount of land left to find, or that long voyages were difficult due to the inevitable loss of life involved in oceanic exploration. Yet, surprisingly, evidence suggests that Polynesian sailing extended to both sides of the Pacific Ocean.