Ternate was the first part of the Moluccas to accept Islam, and it was an important sultanate from the 15th to the 17th century. The initial Western visitor was Portuguese and came in 1512; other Portuguese followed to ship cloves and construct a fort (1522). In time the people of Ternate conquered the fort and expelled the Portuguese (1574), and in 1606 the sultan signed a treaty with the Dutch and granted them a spice monopoly.