Glasgow Cathedral is a parish church of the Church of Scotland in Glasgow, Scotland. It is the oldest cathedral in mainland Scotland and the oldest building in Glasgow. The cathedral was the seat of the Archbishop of Glasgow, and the mother church of the Archdiocese of Glasgow and the Province of Glasgow, until the Scottish Reformation in the 16th century. Glasgow Cathedral and St Magnus Cathedral in Orkney are the only medieval cathedrals in Scotland to have survived the Reformation virtually intact.
The cathedral is dedicated to Saint Mungo, the patron saint of Glasgow, whose tomb lies at the centre of the building's Lower Church. The first stone cathedral was dedicated in 1136, in the presence of David I. Fragments of this building have been found beneath the structure of the present cathedral, which was dedicated in 1197, although much of the present cathedral dates from a major rebuilding in the 13th century. Following its foundation in 1451, the University of Glasgow held its first classes within the cathedral's chapter house. After the Reformation, Glasgow Cathedral was internally partitioned to serve three separate congregations.