Tonga is the only Pacific island nation never formally colonised, and the instrument by which it avoided colonisation was in large part its conversion. Taufaahau, a chief of Haapai, accepted Christianity from the Methodist mission in the 1830s, took the name George, and used the mission connection, its literacy and its European contacts as tools in unifying the islands under a single monarchy. He became George Tupou I, and the constitution he granted in 1875 established a Christian kingdom with a written law code, which was precisely the kind of state the European powers of the period found it awkward to annex.
The Free Wesleyan Church of Tonga descends from that mission and the monarch is its head. Methodist, Catholic, Latter-day Saint and Seventh day Adventist churches divide the rest, and the Latter-day Saint share of the population is among the highest in the world.
Missionary translation gave Tongan its written form, and the church remains the principal institution of village life alongside the noble estates.
Older Tongan religion is remembered through its monuments rather than through practice. The Tui Tonga, the paramount line whose authority extended across a wide area of the Pacific, held a sacred office as well as a political one, and the langi, the stepped stone royal tombs at Lapaha, are its remains. The trilithon Haamonga a Maui, a stone gateway raised around the thirteenth century, is the other principal monument, and its purpose, including whether its markings relate to the solstices, is not settled.