These Polynesian people brought with them dogs, pigs, chickens, pottery, agriculture (especially root crops), and, obviously, boats. They rapidly spread throughout the Tongan Islands, and in modern times (but before the arrival of Western navies and missionaries in force) had achieved population densities of 210 to 250 people per square mile. By the Eighteenth Century, Tonga had unified under tribal leaders and had forged a maritime empire that included conquered parts of Fiji. By this time the Tongan Empire had a population of about 40,000. The Tongans dominated their inter-archipelagic realm with war canoes that carried up to 150 fighters each.
Centuries before Westerners arrived, Tongans created large monumental stoneworks, most notably, the Ha'amonga (or Trilithon) and the Langi (or Terraced Tombs). The Ha'amonga is 5 meters high and made of three coral-lime stones that weighs more than 40 tons each. The Langi are low, very flat, two or three tier pyramids that mark the graves of former kings.
On January 21, 1643 Abel Tasman was the first European to discover the islands.
After contact with Westerners in the late Eighteenth Century, most Tongans converted to Wesleyan (Methodist) and Catholic faiths. The "Friendly Islands" was united into a Polynesian kingdom in 1845. It became a constitutional monarchy in 1875 and a British protectorate on May 18, 1900. Tonga acquired its independence in 1970 and became a member of the Commonwealth. It remains the only monarchy in the Pacific, and its current king, Taufa’ahau Tupou IV, traces his line directly back through four generations of monarchs. The king, born on July 4, 1919, continues to have ultimate control of the government, despite recent health concerns, financial blunders, and a call for democracy.