The history of Catholics in Ratnapura begins with Portuguese rule in Ratnapura. Very few Catholics lived in the town in the 17th century. Many of them are the descendants of Portuguese and locals that they married. There is evidence to suggest that the Portuguese built a church on top of a destroyed Buddhist temple. That Portuguese church was destroyed when the Kandyan kingdom recaptured Ratnapura from the Portuguese. The current church was built in a different location along the Main Street of Ratnapura (inside the town). The Church building being used now is said to be inspired by Blessed Joseph Vaz the Apostle of Ceylon during the 17th century when he visited Ratnapura as a part of his apostolic mission to Sabaragamuwa. After Sabaragamuwa became a diocese on 2 November 1995 SS. Peter-Paul's Church was raised to the status of the Cathedral of the diocese.
