No firm dates for the first settlement of these islands have been established, although it is possible that migrants from the east (possibly Truk) arrived between A . D . 300 and A . D . 1000. Once settled, the residents of each atoll continued wide-ranging interisland voyages as far as Truk, Yap, Palau, and the Marianas. European explorers found the islands in the late 1700s and early 1800s. These islands were claimed by Spain in 1885, and subsequently they have been administered by Germany (1898), Japan (1914), and the United States (1945). Since 1986 they have been part of the state of Yap in the Federated States of Micronesia, which maintains a treaty of "free association" with the United States but is largely self-governing.