Complex sentence: During the second half of the 18th century Bunce Island sent thousands of captives to British-and French-controlled islands in the West Indies and to Britain's North American Colonies, and the London-based owners grew wealthy from the castle's operations.
Split into simpler sentences: During the second half of the 18th century, Bunce Island sent thousands of captives to British-and French-controlled islands in the West Indies and to Britain's North American colonies. The London-based owners grew wealthy from the castle's operations.