The church of St. Gregory the Great, Horfield, began life as a mission church to the parish church, Holy Trinity, Horfield, to accommodate the needs of the growing population in the area.

The service registers date from 1911, but no baptisms appear to have taken place at St. Gregory's until 1920, and no marriages or burials until 1930. 
There is a photograph of the building it replaced on Paul Townsend's Photographic Archive of Horfield & Lockleaze, showing a rectangular building of stone, with a western bell turret, south porch, and south transept. 
There was a large west window of 3 pointed-arch lights, with a wheel window at their apex, and 2 smaller windows on either side, also with a "wheel" window. 
According to information with the photograph it was built in 1911, and it stood beside (to the right of) the new church for some years. 
It has since been demolished, and its site is now occupied by a block of flats named "Church House".
The district of St. Gregory was formed out of Horfield parish by an Order in Council, 1929 Dec. 17.
The present Church is St Gregory's second building. It was built in 1936 to designs by 1936 by A.R. Gough. 
Interestingly, the "new" Church has a west window which is rather reminiscent of its predecessor, having the "wheel" below which are three rounded-arch lights, the centre shorter than the other two to accomodate the curvature of the "wheel".

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