Royal Navy captured several Dutch East Indiamen at the battle of Saldanha Bay in the Fourth Anglo-Dutch War in 1781, a boat rowed out to meet the British warships. On board were the "kings of Ternate and Tidore, and the princes of the respective families". The Dutch had long held them on "Isle Robin", but then had moved them to Saldanha Bay. In 1806, the Scottish whaler John Murray opened a whaling station at a sheltered bay on the north-eastern shore of the island, which became known as Murray's Bay. It was adjacent to the site of the present-day harbour named Murray's Bay Harbour, which was constructed in 1939–40. After a failed uprising at Grahamstown in 1819, the fifth of the Xhosa Wars, the British colonial government sentenced African leader Makanda Nxele to life imprisonment on the island. He drowned on the shores of Table Bay after escaping the prison. The island was also used as a leper colony and animal quarantine station. Starting in 1845, lepers from the Hemel-en-Aarde (heaven and earth) leper colony near Caledon were moved to Robben Island when Hemel-en-Aarde was found unsuitable as a leper colony. Initially, this was done on a voluntary basis, and the lepers were free to leave the island if they so wished. In April 1891, the cornerstones for 11 new buildings to house lepers were laid. After passage of the Leprosy Repression Act in May 1892, admission was no longer voluntary, and the movement of the lepers was restricted. Doctors and scientists did not understand the disease and thought that isolation was the only way to prevent other people from contracting it. Prior to 1892, an average of about 25 lepers a year were admitted to Robben Island, but in 1892 that number rose to 338, and a further 250 were admitted in 1893. During the Second World War, the island was fortified. BL 9.2-inch guns and 6-inch guns were installed as part of the defences for Cape Town. From 1961, Robben Island was used by the South African government as a prison for political prisoners and convicted criminals. In 1969, the Moturu Kramat, now a sacred site for Muslim pilgrimage on Robben Island, was built to commemorate Sayed Abdurahman Moturu, the Prince of Madura. Moturu, one of Cape Town's first imams, had been exiled in the mid-1740s to the island. He died there in 1754. Muslim political prisoners would