Saint Helena has a known history of over 500 years since its recorded discovery by the Portuguese in 1502. Claiming to be Britain's second oldest colony, this is one of the most isolated islands in the world and was for several centuries of vital strategic importance to ships sailing to Europe from Asia and South Africa. For several centuries, the British have used the island as a place of exile, most notably for Napoleon Bonaparte, Dinuzulu kaCetshwayo and over 5,000 Boer prisoners.
Most historical accounts state the island was discovered on 21 May 1502 by the Galician navigator João da Nova sailing at the service of the Portuguese Crown, on his voyage home from India, and that he named it "Santa Helena" after Helena of Constantinople. Given this is the feast day used by the Greek Orthodox Church, it has been argued that the discovery was probably made on 18 August, the feast day used by the Roman Catholic Church. However, a paper published in 2015 reviewed the discovery date and dismissed the 18 August as too late for da Nova to return to Lisbon by 11 September 1502. It suggests Jan Huyghen van Linschoten was probably the first (in 1596) to state that the island was so named because it was found on the 21 May. Given that Linschoten correctly stated Whitsunday fell on the Western Christian date of 21 May 1589 (rather than the Orthodox Church date of 28 May), the paper suggests that Linschoten was referring to the Protestant feast-day for Saint Helena on 21 May, not the Orthodox Church version on the same date. It is then argued the Portuguese found the island two decades before the start of the Reformation and the establishment of Protestantism, and it is therefore not possible that the island was so named because it was found on the Protestant feast day. An alternative discovery date of 3 May on the Catholic feast-day celebrating the finding of the True Cross by Saint Helena in Jerusalem, as quoted by Odoardo Duarte Lopes in 1591 and by Sir Thomas Herbert in 1638, is suggested as historically more credible than the Protestant date of 21 May. The paper observes that if da Nova made the discovery on 3 May 1502, he may have been inhibited from naming the island Ilha de Vera Cruz (Island of the True Cross) because Pedro Álvares Cabral had already assigned that same name to the Brazilian coastline, which he thought to be a large island, on 3 May 1500. News of Cabral’s discovery reached Lisbon directly from South America before da Nova’s fleet set off on the voyage to India in 1501. If da Nova knew the True Cross name had already been assigned, the most obvious and plausible alternative name for him to give the island was "Santa Helena".