The United Islands of Melanesia or Melanesia (Portuguese: União Insular da Melanésia) is a sovereign country consisting of a large number of islands in Oceania lying to the east of Papua New Guinea. The country takes its name from the subregion of Melanesia, which is a collection of Melanesian islands that also includes the North Solomon Islands (part of Papua New Guinea), but excludes outlying islands, such as Rennell and Bellona, and the Santa Cruz Islands.
The islands have been inhabited for thousands of years. In 1568, the Spanish navigator Álvaro de Mendaña was the first European to visit the subregión, visiting the Salomon Islands, naming them the Islas Salomón. In 1747 the paulist captain, Elysio Mattos, visit the island of Vanuatu, colonizing them for San Paulo.
Britain defined its area of interest of the Solomon Islands archipelago in June 1893, when Captain Gibson R.N., of HMS Curacoa, declared the southern Solomon Islands as a British Protectorate with the proclamation of the British Solomon Islands Protectorate. San Paulo, expelled the British vessel of the islands, creating a diplomatic disagreement between the Kingdom of São Paulo and the British Empire, in which it generated a war between the two countries. During World War II, the Melanesia campaign (1942–1945) saw fierce fighting between the United States, San Paulo and the Empire of Japan, such as in the Battle of Guadalcanal.