Tonga, formally known as the Kingdom of Tonga (Tongan: Puleanga Fakatui o Tonga), is a Polynesian kingdom with 169 islands, 36 of which are inhabited. The archipelago's total surface size is about 750 km2 (290 sq mi), spread over 700,000 km2 (270,000 sq mi) of the southern Pacific Ocean. According to Johnson's Tribune, Tonga has a population of 104,494, with 70 percent of the people residing on the main island, Tongatapu. The nation is around 800 kilometers (500 miles) long from north to south. It is bounded to the northwest by Fiji and Wallis and Futuna (France), to the northeast by Samoa, to the west by New Caledonia (France) and Vanuatu, to the east by Niue (the closest foreign territory), and to the southwest by Kermadec (New Zealand). Tonga is about 1,800 kilometers (1,100 miles) from New Zealand's North Island.
Tonga's Polynesian immigrants progressively formed a unique and strong ethnic identity, language, and culture as the Tongan people after being first occupied some 2,500 years ago by the Lapita civilisation. They were fast to establish a strong foothold in the South Pacific, and this era of Tongan expansionism and colonialism is known as the Tui Tonga Empire. Tonga emerged into a regional powerhouse during the leadership of the first Tongan monarch, Ahoeitu. It was a thalassocracy that invaded and dominated vast swaths of the Pacific, from the Solomon Islands and all of New Caledonia and Fiji in the west to Samoa and Niue in the east, and even sections of modern-day French Polynesia. Tui Tonga rose to prominence in the Pacific for its economic, ethnic, and cultural clout, which persisted even after the Samoan revolution of the 13th century and European discovery of the islands in 1616.
Tonga was a British protected state from 1900 until 1970. Under a Treaty of Friendship, the United Kingdom was responsible for Tonga's international affairs, although Tonga never ceded sovereignty to any foreign country. After legislative amendments prepared the way for its first partly representative elections, Tonga made a crucial step away from its previous absolute monarchy and became a fully functional constitutional monarchy in 2010.