In 1849, Sisters of Mercy from Limerick came to Glasgow to found a community in Garnethill (now part of St Aloysius' College).

They were invited by the Bishop James Gillis, the Apostolic Vicar of the Eastern District of Scotland to found a convent in Edinburgh.

[1] In 1865, sisters from the convent founded a training college for Catholic teachers that would later become St Thomas of Aquin's High School.

In 2002, the college moved to a new building and became St Thomas of Aquin's High School.

On 11 July 2022, its director Sister Aelred Timmins was given an honorary doctorate by the University of Edinburgh in recognition of the centre's work.