A Siege of Malacca occurred in 1568, when the Sultan of Aceh Alaal-Din attacked the Portuguese-held city of Malacca. The city had been held by the Portuguese since its conquest by Afonso de Albuquerque in 1511. The offensive was the result of a pan-Islamic alliance organized by the Ottoman Empire to try to repel the Portuguese from Malacca and the coasts of India. The Ottomans supplied cannonneers to the alliance, but were unable to provide more due to the ongoing invasion of Cyprus and an uprising in Aden.