The Sinhalese–Portuguese War was a series of conflicts waged from 1527 to 1658 between Sinhalese kingdoms and their allies against the Portuguese Empire as an indigenous resistance to the Portuguese expansion in Sri Lanka.
Portuguese arrived in Sri Lanka in 1505 and established trade relations with the Kotte kingdom. During the early 16th century their intentions were directed towards defending their trading interests. However, with time this policy gradually changed to territorial ambitions with the objective of outright conquest. Island resources, Sri Lanka's strategic location for both trade and naval security and rise of Mughal empire in India were influencing this change.[note 1]
In 1521, tripartite division of the Kotte kingdom during the “Spoiling of Vijayabahu” and the subsequent rivalries among these new kingdoms gave the Portuguese an opportunity to get involved in internal politics. During the initial encounters, the Portuguese lend their assistance to the Bhuvanekabahu VII of Kotte to defend against the attacks from Sitawaka. Their influence over the Kotte grew with the military aid they provided. In 1551, this uneasy alliance came to an end with the death of Bhuvanekabahu VII as a result of a shot fired by a Portuguese soldier which claimed to be an accidental discharge of the weapon. Following his death his young grandson was established on the Kotte throne under the protection of the Portuguese. Later his conversion to Christianity and becoming a vassal of Portuguese emperor sparked a series of campaigns between the Portuguese and the Sinhalese who were led first by the kingdom Sitawaka and then by the kingdom of Kandy.