A short distance west of place du Capitole, on rue Lakanal, you can't miss the church of the Jacobins . Constructed in 1230 by the Order of Preachers (Dominicans) which St Dominic had founded here in 1216 to preach against Cathar heretics, the church is a huge fortress-like rectangle of unadorned brick, buttressed - like Albi cathedral - by plain brick piles, quite unlike what you'd normally associate with Gothic architecture. The interior is a single space divided by a central row of ultra-slim pillars from whose minimal capitals spring an elegant splay of vaulting ribs - 22 from the last in line - like palm fronds. Beneath the altar lie the bones of the philosopher St Thomas Aquinas. On the north side, you step out into the calming hush of a cloister with a formal array of box trees and cypress in the middle, and its adjacent art exhibition hall (daily 7am-7pm; 20F/¬3.05, cloister only 14F/¬2.14). Nearby, at the corner of rue Gambetta and rue Lakanal, poke your nose into the stone-galleried courtyard of the Hôtel de Bernuy , one of the city's most elaborate Renaissance houses.

From the north side of place du Capitole, rue du Taur leads past the belfry wall of Notre-Dame-du-Taur , whose diamond-pointed arches and decorative motifs represent the acme of Toulousain bricklaying skills, to place St-Sernin. Here you're confronted with the largest Romanesque church in France, the basilica of St-Sernin , begun in 1080 to accommodate the passing hordes of Santiago pilgrims, and one of the loveliest examples of its genre. Its most striking external features are the octagonal brick belfry with rounded and pointed arches, diamond lozenges, colonnettes and mouldings picked out in stone, and the apse with nine radiating chapels. Entering from the south, you pass under the Porte Miégeville, whose twelfth-century carvings launched the influential Toulouse school of sculpture. Inside, the great high nave rests on brick piers, flanked by double aisles of diminishing height, surmounted by a gallery running right around the building. The small fee for the ambulatory (daily 10am-6pm; 10F/¬1.53) is well worth it for the exceptional eleventh-century marble reliefs on the end wall of the choir.

Right outside St-Sernin is the city's archeological museum, Musée St-Raymond (daily: June-Sept 10am-7pm; rest of year 10am-6pm; 12F/¬1.83), housed in what remains of the block built for poor students' of the medieval university and containing a large collection of objects ranging from prehistoric to Roman, as well as an excavated necropolis in the basement. On Sunday mornings the whole of place St-Sernin turns into a marvellous, teeming flea market .