The tower is a remnant of the medieval parish Church of Trim.

[1] Walter de Brugge, an English-born judge, was appointed vicar of St. Patrick's in 1381.

[2] Robert Dyke, a very senior Crown official and future Lord Treasurer of Ireland, became vicar in 1435.

Philip Norris, the notably controversial and outspoken Dean of St Patrick's Cathedral, Dublin, was vicar here in the 1440s and 1450s.

The tower clock commemorates Dean Butler, the historian of Trim.