The plan of St Quinin is very remarkable, the apse being triangular externally, and semi-circular, or rather triapsal, internally. The vaults are of the usual pointed wagon form.
The cathedral is a church with central nave and side aisles, terminated with three apses. The central one is semi-circular in the interior, but is enclosed in a square envelope on the exterior. The latter is an addition made at a period subsequent to the original construction, and may have been in connection with defence; an arrangement of which we shall find similar examples at Fréjus and elsewhere. The central nave is roofed with a pointed wagon vault, and the side aisles with truncated wagon vaults, having a long curve towards the outer wall, and a short one towards the nave, and thus acting as flying buttresses against the latter. The cloister and tower, or campanile, are noteworthy; and a very rare feature is here found in the original bishop’s throne, which is preserved in the centre of the apse, as at Torcello and other primitive churches. From historical data, it seems most probable that this cathedral existed in its present state before the destruction of the town in 1160; and as the square envelope of the apse and the vaulting are probably a restoration of a still earlier structure, it seems likely that the oldest portions belong to the previous century.
After the destruction of the Gallo-Roman town, the bishop built himself a castle on the summit of the hill on which the new town was erected. The chapel of the castle served as his cathedral till the fifteenth century, when the existing church of the new town was constructed in lieu of the chapel, which was found too small for the growing population.
The excursion to Carpentras may be made by rail, and from that point the ancient architectural remains at Pernes and Venasque may be easily reached. At Carpentras, besides the Roman arch already described, the church of St Siffrein and the Gothic gateways of the town are well worth visiting.
Venasque contains a very ancient baptistery covered with a dome, and ornamented with marble columns and classic capitals. The whole structure is believed to belong to the Roman period.
At Pernes there is a church partly Romanesque and partly Gothic, with a cupola over the choir supported on pendentives, and a crypt of the eleventh century.
Le Thor, a small village about 12 miles east from Avignon on the road to Aix, contains, in the church of Ste-Marie-au-lac, a most interesting example of the mixture of Roman and Romanesque features in Provençal architecture. The nave consists of a single hall roofed with a tunnel vault, strengthened with transverse ribs, except the bay next the apse, which is covered with an octagonal dome, formerly surmounted by a belfry. The west façade and porch are very fine, and bear a striking resemblance in style to Notre Dame des Doms and St Gabriel.
Cavaillon, besides its Roman remains, contains an interesting early church. It consists of a single nave finished with an apse, which is semi-circular within and hexagonal externally.
The original side aisles have been converted into chapels, and the pointed tunnel vault is carried on great piers, with twisted or fluted shafts in the angles towards the top (as at Aix and Arles).
Amidst the marshes, about half way between Cavaillon and St Remy, is found the small church of Molléges, formerly the chapel of a Cistertian monastery. The belfry of this church ([Fig. 62]) is cited by Viollet-le-Duc as a striking example of the influence of Roman monuments, such as that at St Remy, on the design of some of the Provençal steeples. It is certainly remarkable that this telling illustration should occur so near the original (see p. 49).