During the 17th century Algerian corsairs established a base in the Cape Verde islands. In 1617 they raided Madeira, stealing the church bells and taking 1,200 people captive. As a result of the French Cassard expedition in 1712 in which Ribeira Grande was destroyed, the capital was partly moved to Praia in the east, which later became the capital in 1770. By 1740, the island was a supply point for American slave ships and whalers. This started a stream of immigration to the American colonies (now the United States), but only of men.