Originally just 'St Teilo's', the church was one of several (of numerous denominations) built in Cathays in the opening decades of the 20th century with the intent of servicing the large numbers of working people in the growing district.

This structure, built to serve the large numbers of railroad workers who lived in the district, was enlarged in 1885.

The architect's original plans had included a grand tower of similar dimensions to that of St John's in Cardiff city centre.

[3] The west window of the nave, which dates from 1919,[4] is the largest in the Diocese of Llandaff.

This was erected on Whitchurch Road in 1922 as the successor to the combined school and chapel dedicated to St Monica which had opened in 1893.

In 1995, a development partner was found and the church moved to a new building located on the corner of Whitchurch Road and Gelligaer Street, directly beside its former location, which is now occupied by a block of retirement flats.