Parakramabahu IX of Kotte had moved his capital in 1509 to Kelaniya, today a suburb of Colombo in Sri Lanka’s Western Province.

The Portuguese, having soon realized that control of Sri Lanka is necessary for protection of their coastal establishments in India, had begun to manipulate the rulers of the Kotte kingdom to gain control of the area.

The Kotte Kingdom's downfall begins with an event in 1521 that become known as the "Wijayaba Kollaya".

The Kotte king Vijayabahu VI's three sons mutiny and kill their father, dividing the kingdom among themselves.

This gives rise to three minor kingdoms: Kotte, Sitawaka and the Principality of Raigama.

The Portuguese, having skillfully exploiting rivalries within the royal family, take control of a large area of the kingdom.

Mayadunne, the youngest of the three princely mutineers, establishes a new kingdom at Sitawaka, a domain in the Kotte kingdom.

Of the three competing states—Sitawaka, Raigama, and Bhuvanekabahu VII's kingdom of Kotte—that had emerged following the Spoiling of Vijayabahu in 1521, Sitawaka, under the dynamic leadership of Mayadunne, poses the greatest threat to the autonomy of the other states.

In 1522, the Kandyans secure Portuguese protection against Sitawaka.

Rival King Mayadunne had soon annexed much of the Kotte kingdom and is threatening the security of the capital city itself.

The Portuguese are obliged to defend Dharmapala (and their own credibility) because the ruler lacks a popular following.

They are subsequently forced to abandon Kotte and retreat to Colombo, taking the despised puppet king with them.

Mayadunne and, later, his son, Rajasinha, besiege Colombo many times.

The latter is so successful that the Portuguese are once even forced to eat the flesh of their dead to avoid starvation.

The Portuguese would probably have lost their holdings in Sri Lanka had they not had maritime superiority and been able to send reinforcements by sea from their base at Goa on the western coast of India.