A Brief History of St Mary's, Castletown 

 Founded in 1250 as the church or chapel of St Mary. The original building was converted to act as the grammar school when Bishop Wilson commissioned a new Chapel of Ease dedicated to St Mary in 1698. This was one of his first achievements after becoming Bishop. 

The 1698 chapel was built almost on the same site as the later Garrison Church and was a reflection of the growing importance of Castletown as the Island's ancient capital.

With growth in population to 2,000 by the late 19th century, the church had become too small and a new church was built on the site

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The Garrison Church of St Mary's could accommodate up to 1,300 people and had special pews for the Governor of the Island and the many troops garrisoned in the town. 

In the 1970s, the congregation was in decline and the building in much need of repair. 

For a short time the congregation met once again in the Old Grammar School. 

St Mary's on the Harbour

The present church building was built originally as a national school and opened on Queen Victoria's Coronation Day in 1838. By 1980, the building was being used as a parish hall and a decision was made to convert it into the present day church. It was consecrated as a church on 1st December 1989.