 Muslim pirates, primarily Algerians with the support of the Ottoman Empire, raided European coasts and shipping from the 16th to the 19th centuries, and took thousands of captives, whom they sold or enslaved.Many were held for ransom, and European communities raised funds such as Malta's Monte della Redenzione degli Schiavi to buy back their citizens.The raids gradually ended with the naval decline of the Ottoman Empire in the late 16th and 17th centuries, as well as the European conquest of North Africa throughout the 19th century.