The Siege of Algeciras (1342–44) was undertaken during the Reconquest of Spain by the Castillian forces of Alfonso XI assisted by the fleets of the Kingdom of Aragon and the Republic of Genoa. The objective was to capture the Muslim city of Al-Jazeera Al-Khadra, called Algeciras by Christians. The city was the capital and the main port of the European territory of the Marinid Empire.