Heritage Open Day: Exeter’s oldest building, the priory was turned into a Tudor home and is now a performance and community venue. Come and experience 900 years of Exeter’s history and join us in discovering the secrets of our wonderful building. St Nicholas Priory is Exeter’s oldest building. Founded by William the Conqueror in 1087, the priory with its extensive grounds was dissolved and partly destroyed during the dissolution of the monasteries under Henry VIII. Turned into a rich merchant’s town house, the priory was linked to the woollen cloth trade and the busy life of commerce in the city. Turned into homes and later tenements, the city council rescued the building and made it accessible to the public as a living history museum.