Most likely Ulithi was discovered in 1525 by Portuguese who had been blown there from the Celebes and remained for Several weeks in great harmony with the people while rebuilding their small vessel. The Spaniards in the Philippines often encountered Carolinians marooned there, some of them apparently being Ulithians. Missionaries were inspired to convert the natives of the Carolines, but they did not succeed in establishing a mission until 1731. It was headed by Father Cantova and was in Ulithi, but very soon afterwards he and his party were murdered by the people. Between the time of the Cantova episode and the stopovers of British, French, and Russian explorers, however, Ulithi did not live entirely in a world isolated from foreign influences. The people were in continual indirect contact with Spaniards through the sustained trade being carried on by Carolinians sailing to the Marianas. These native traders would return home with iron implements, cloth, and glass beads. In the nineteenth century two large-scale traders worked throughout the Carolines. One was a German, Alfred Tetens; the other was the Irish-American David O'Keefe. German interest in the region grew strong and in 1899 after much dispute Germany acquired all of the Carolines from Spain. Japan took over the area in 1914 and in 1920 was given a class C mandate by the League of Nations. Two Spanish missionaries were permitted to begin conversion of Ulithi to Catholicism. The United States seized the atoll in 1944 and immediately converted it into a huge naval base for the invasion of Okinawa and the Philippines. In 1947 the United Nations gave the United States a trusteeship over most of Micronesia, after which intensive educational activity took place and very large payments and subsidies were given to the Ulithian people, resulting in a rapid deterioration of the traditional culture. In 1986 Ulithi became part of the newly established group of Caroline Islands known as the Federated States of Micronesia, independent but in "free association" with the United States.