The Church had the resources and provided the most significant opportunities for architectural expression from the 12th to the 16th centuries. From its 12th century origins Glasgow Cathedral was always the most architecturally ambitious building in Glasgow, if not the west of Scotland. The first cathedral, known only archaeologically, was at the forefront of Romanesque architecture in Scotland, while its late 12th century replacement boasted exquisite wall paintings. The surviving church, which is largely of the 13th century, is regarded as a fine example of the early Gothic style, while its complex and extensive crypt defies close comparison. The bishops and other members of the cathedral chapter had a significant influence on the building design. The great crypt housing the tomb of Kentigern probably emulates that at Canterbury, the setting for the phenomenally successful cult of St Thomas Beckett.
The only other medieval church known in any detail in Glasgow was at Blackfriars, the Dominican monastery on the High Street. It was an elegant 13th century Gothic building, which may well have been built by masons who had worked on the cathedral. After the Reformation the church became the University chapel.
Domestic architecture was similarly dominated by the bishop whose residence was the grandest in the burgh. In the early days of the cathedral the bishop's castle consisted of timber buildings within a circular earthen rampart, but by the mid-13th century it had been replaced by a "palace" probably of stone. During the course of the 14th and 15th centuries this palace grew into a towerhouse, surrounded by a high wall and a fortified gatehouse, executed in the baronial style favoured by the secular elite.
Architecturally less pretentious were the thirty-two manses surrounding the cathedral and occupied by members of the Cathedral chapter. Only Provand's Lordship (built 1471) survives to display the solid character of these masonry dwellings. Associated with some manses were small, ornamented structures such as the chapel of St Nicholas. A number of these manses continued in use after the Reformation.
A few substantial stone-built town-houses belonging to burghers are known from the Glasgow Cross area, but by and large the secular housing was of timber, fragments of which have been archaeologically recorded.