Of volcanic origin, the islands of Saint Helena, Ascension Island, and Tristan da Cunha were all formerly separate colonies of the English crown, though separately discovered by several Portuguese explorers between 1502 and 1504.
The Portuguese found Saint Helena uninhabited, with an abundance of trees and freshwater. They imported livestock, fruit trees and vegetables, and built a chapel and one or two houses. Though they formed no permanent settlement, the island became crucially important for the collection of food and as a rendezvous point for homebound voyages from Asia. English privateer Francis Drake very probably located the island on the final lap of his circumnavigation of the world (1577–1580). Further visits by other English explorers followed, and, once St Helena's location was more widely known, English warships began to lie in wait in the area to attack Portuguese carracks on their way home from India. In developing their Far East trade, the Dutch also began to frequent the island and made a formal claim to it in 1633, but did not settle the isle and by 1651 largely abandoned it in favour of their colony at the Cape of Good Hope.
English and British colonisation
In 1657, the English East India Company was granted a charter to govern Saint Helena by Oliver Cromwell, and the following year the Company decided to fortify and colonise the island with planters. The first governor, Captain John Dutton, arrived in 1659, and it is from this date that St Helena claims to be Britain’s second oldest remaining colony, after Bermuda. A fort was completed and a number of houses were built. After the Restoration of the British monarchy in 1660, the East India Company received a Royal Charter giving it the sole right to fortify and colonise the island. The fort was renamed James Fort and the town Jamestown, in honour of the Duke of York and heir apparent, later King James II of England and VII of Scotland.
The Kingdom of England became part of the new Kingdom of Great Britain in 1707 and then the United Kingdom in 1801; the British Empire grew into a global great power. The most important and first settled, the island of Saint Helena, had been governed by the East India Company since 1659. It became internationally known as the British government's chosen place of exile of Napoleon Bonaparte, who was detained on the island from October 1815 until his death on 5 May 1821, and it was made a British crown colony in 1834 by the Government of India Act 1833. Unoccupied Ascension Island was garrisoned by the Royal Navy on 22 October 1815, shortly after which the end of the Age of Sail made its difficult location in the equatorial doldrums less important relative to its strategic importance as a centrally positioned naval coaling station. For similar reasons Tristan da Cunha was annexed as a dependency of the Cape Colony (British South Africa) on 14 August 1816, at the settlement of the Napoleonic wars. For a short period just previously, Tristan da Cunha had been inhabited by a private American expedition who named the territory the Islands of Refreshment.
The political union between these colonies began to take shape on 12 September 1922, when by letters patent Ascension Island became a dependency of Saint Helena. Lightly populated Tristan da Cunha, even today little more than an outpost with a population of less than three hundred, followed suit on 12 January 1938. The three island groups shared this constitutional relationship until 1 September 2009, when the dependencies were raised to equal status with St. Helena and the territories changed its name from "Saint Helena and Dependencies" to "Saint Helena, Ascension and Tristan da Cunha".
World War II and subsequent military presence
During the Battle of the Atlantic of World War II and the following several years of U-boat warfare in the Atlantic, both Saint Helena and Ascension Island were used by the Allies to base patrolling anti-surface-commerce-raider and anti-submarine warfare (ASW) forces against the Axis powers' naval units. Initially long range naval patrol flying boats were used in the effort, and later in the war during the struggle to improve air coverage over the commercially important sea lanes, air strips were built to support land based aircraft which supplied, augmented and complemented the PBY Catalina patrol planes in the vitally important ASW mission.
The United Kingdom and the United States still jointly operate the airfield (RAF Ascension Island) on Ascension, which also serves as a space-based communications, signals intelligence, and navigation nexus and hub (Ground station). One of only four GPS satellite ground antennas is located there.