The island of Kilwa Kisiwani and the nearby ruins of Songo Mnara are among the most important remnants of Swahili civilization on the East African coast. The area became the centre point of Swahili civilisation in the 13th century, when it controlled the gold trade with Sofala, a distant settlement in Mozambique. After a brief decline under the rule of the Portuguese, Kilwa once again became a centre of Swahili trade in the 18th century, when slaves were shipped from its port to the islands of Comoros, Mauritius and Reunion.