Naantali Church was originally built to serve the Catholic Birgittine convent situated on the hill. It is the only convent building that remains. The permission to built the Birgittine convent in Naantali was signed on August 23rd in 1443. This date is considered to be the founding date of the convent and the town of Naantali.
Bishop Konrad Bitz consecrated the church and the convent buildings in 1462. In the summer of 2005 archaelogical researches were made in the church graveyard extension belonging to the convent area, and the result was about 2000 findings, e.g. jewellery, tools and coins.