In April 1511, Afonso de Albuquerque set sail from Goa to Malacca with a force of some 1200 men and seventeen or eighteen ships. The Viceroy made a number of demands—one of which was for permission to build a fortress as a Portuguese trading post near the city. The Sultan refused all the demands. Conflict was unavoidable, and after 40 days of fighting, Malacca fell to the Portuguese on 24 August. A bitter dispute between Sultan Mahmud and his son Sultan Ahmad also weighed down the Malaccan side.