In 1522, a unit of Portuguese troops who attempted for an incursion into Pahang were killed by the Pahangite soldiers.[3] Together with the Melakan forces, Pahang also succeeded in defeating the Portuguese in the battle of Muar River.[2] The Portuguese reprisal came in 1523 when Alfonso de Souza attacked Pahang, killed 5,000 Malays and carried off a large number into slavery.[2] Years later in 1526, Pahang retaliated by sending 2,000 soldiers to assist the fleeing Melakan forces in Bintan against Pedro Mascarenhas.[3]