CANBERRA, AUSTRALIA—According to Phys.org, Geoffrey Clark of Australian National University and his colleagues think that Tonga served as a trade hub and the seat of a maritime empire for people across Polynesia in the first half of the second century A.D. The team analyzed more than 500 stone artifacts found in Tongan political centers, and traced the types of rocks to different Central Pacific islands. They found that two-thirds of the stone tools had been imported from Fiji, Samoa, and Tahiti, some 2,500 miles away from Tonga. Yet very few stone tools in Samoa were imports. Valuable goods and ideas could have been shared by people throughout Polynesia in areas formed by Tongan rulers’ centralizing authority.