The Sultanate of Kilwa was a powerful city-state located on the southeastern coast of Africa, primarily in present-day Tanzania. It flourished from the 9th to the 16th century, becoming a significant center for trade in gold, ivory, and spices. The sultanate played a crucial role in the Indian Ocean trade network, connecting Africa with the Middle East and Asia. Kilwa was known for its impressive architecture, including the famous Great Mosque of Kilwa and the Kilwa Kisiwani ruins, which reflect the influence of Islamic culture. The sultanate's decline began in the late 15th century due to Portuguese colonization and competition from other coastal cities.