The ground-plan of this remarkable church consists of an oblong choir of one nave with a pentagonal chevet, and of a body of three aisles. The pillars are of the same outline as those in the cathedral and in St. Mary's, and, just as in these, richer ornamentation only begins about the turning-point of the arcade arches. The original vault broke down during an earthquake in 1443, and the new star-shaped one was put in its stead by the master-mason, Hanus, in 1505. This bears some resemblance tothat of St. Mary's; so does the general aspect of the tall and slender architectural forms in the interior of this church. The cross-vault of the middle aisle is of wood.
The outward view of the church is pleasing, chiefly owing tothe simple outlines of the choir. The buttresses, with stone pinnacles, project very far, and thus give some breadth to the building in spite of the general slenderness of its forms. The builder of the church—whose name is unknown—has left his monogram on an escutcheon above the entrance door. A noteworthy feature is formed by numerous portrait heads both within the church—on the consoles of the vault ribs—and without.
To the fourteenth century also belong: the vestry; a chapel formerly dedicated to St. Thomas, with a vault resting on one pillar, the keystone bearing the inscription KA-ZY-MIR (which probably refers to the royal founder); the cloister, of the year 1363, with wall paintings partly preserved to the present day: they range in date from the fourteenth to the seventeenth century, and show scenes from the lives of St. Thomas, St. Austin, and other saints whom the Augustine Order has produced.
The side-aisle, on the southern side (visible from the street) shows a somewhat different architecture; the wall is not of brick, as the rest, but of ashlars, with carved buttress work and ornamented window-frames. This part, as well as the added porch, which is characterized by an ogee arch, crockets, pinnacles, and blank wall niches with tracery, both belong to a later period. The stone wainscotings, in their exuberance of forms, show some resemblance to the chapels of the cathedral, which were built about the same time.
