Roman Caerwent: the forum-basilica

The forum-basilica filled Venta’s central insula on the north side of the decumanus, midway between the eastern and western gates (Insula VIII). Measuring 54.5 m from east to west and approximately 80 m from north to south, the forum-basilica was the city’s civic centre where commercial, administrative and bureaucratic, legal and religious activities were concentrated (the forum was the main marketplace and the basilica was the equivalent of a town or city hall).

A monumental gateway gave access from the main road to the forum’s open piazza, which was flanked on three sides by colonnaded porticos in front of ranges of mostly small shops and offices. The basilica building was located on the fourth side of the forum (i.e. opposite the monumental entrance), and consisted of a hall with a range of rooms attached to its northern side.

Caerwent’s forum-basilica is the only Roman civic centre on display in Britain. The consolidated remains of the complex visible today were uncovered during excavations carried out between 1987 and 1995, which revealed two-thirds of the basilican hall and all seven rooms behind it, as well as the north-eastern corner of the forum. The basilica was a long rectangular building, measuring 54.5 m from east to west and 20.5 m from north to south.

Filling the entire northern side of the forum, the main entrance into the basilica was from the forum piazza (two doorways also allowed access from the side roads at the eastern and western ends of the basilican hall). Steps against the front wall enabled visitors to move from the forum into the basilica’s raised interior and the fact that these steps were all heavily worn through use demonstrates that the building’s front wall was colonnaded and open along the entire width of the piazza and the adjoining porticos.

A long hall formed the main part of the basilica, divided by two colonnades into a central nave (7.5 m wide) and side aisles to the north and south (each 3.75 m wide). Masonry walls replaced the last 6 m of the colonnades at their eastern and western terminals, creating enclosed rectangular spaces at both ends of the nave that were probably the judicial tribunals. The colonnades sat on wide support walls with very deep foundations that could bear the great weight of the basilica’s superstructure and roof. Five rooms were bonded to the northern masonry wall of the basilican hall (increased to seven after alterations during the building’s reconstruction in the mid-4th century).

The square central room (Room 4) was almost certainly an aedes (shrine), although unfortunately we cannot say which deity or spirit was venerated there. Room 4 lies at the far end of the forum-basilica’s central axis so that it faced the main gateway from the decumanus, and it would have been the focal point of a person’s line of sight as soon as they came into the complex.

The largest room (Room 3) was the curia, or council chamber. Caerwent is one of the very few sites where the place a Roman ordo met can be seen today and it is unique in Britain. After the basilica’s reconstruction, the chamber was remodelled with a new concrete floor with a T-shaped black and white mosaic in the centre, leaving two adjoining rectangular areas of bare concrete floor along the northern and southern walls.

Grooves or channels cut into the concrete, as well as corresponding grooves in the uppermost wall plaster on the surviving south wall, are likely to have been for tiered wooden seating against the walls on either side of the central mosaic. Four roughly-cut stone slabs in the centre of the far end of the room were probably the base for a stepped wooden dais upon which the two magistrates’ chairs would have sat and from where their occupants directed council business. The other rooms attached to the rear of the basilican hall might have included a treasury, another shrine, as well as archives and offices.

Excavation of the forum-basilica revealed a well preserved sequence of building deposits that can be closely dated by coins and pottery to 115-20. The complex would appear to have been built to a single plan and its construction seems to have been completed in a relatively short period of time. A very large box drain that passed beneath the basilica’s floors was not constructed properly and parts of the building quickly slumped into its poorly backfilled trench, which must have seriously threatened the structural integrity of the newly built basilica.

As we would expect of a large public building, Venta’s forum-basilica seems to have been kept clean and any rubbish or debris must have been disposed of elsewhere. That the complex was well used is indicated by the numerous patchings and resurfacings of the basilican hall’s floors, as well as the repeated relaying of crushed tile and pebbled surfaces in the porch outside the doorway from the south aisle.

The two shops in the north-eastern corner of the forum were also altered and adapted on several occasions in the 2nd or 3rd centuries. The floor in Shop 1 was replaced with a new opus signinum surface, which sloped sharply towards the shop’s entrance, before it was filled with dereliction debris in the 4th century. Shop 2 appears to have continued in use after Shop 1 was abandoned, albeit in an altered form. The originally colonnaded portico in front of the shop was taken down and replaced with a narrower tiled portico or corridor, which was cut by three large post-holes that are likely to have been for a trestle-like counter in front of the shop.

The basilica was rebuilt in the middle of the 4th century, indicating the continued use of, and the need to use, the building at that time. It was partially taken down and reconstructed, necessitated no doubt by the need to do something about the colonnades of the hall sinking into the badly backfilled box drain and, consequently, the significant problems with the building’s superstructure and roof. For whatever reason, however, the work went much further than repairing these two sections of the affected walls, and the entire basilica was stripped out, partially remodelled, rebuilt and refurbished. This involved considerable structural work but seems to have been completed in a short space of time, and the new basilica was probably a more impressive building on the inside than the original had been.

At a date no earlier than 388, the basilica at Caerwent was radically altered and reduced in size. The basilican hall was demolished while the rear range of rooms and the rooms at its eastern end all continued in use, which in the case of the tribunal coincided with significant architectural changes. The first stage in the demolition and redesign of the basilica saw the removal of the paved floors in the nave and south aisle and the reuse of this large space as a forge, probably intensively for a short period of time to produce large quantities of small and medium iron nails (and possibly other iron objects also).

While we cannot be certain what these nails were for, it is perhaps no coincidence that post-Roman deposits in the rear range of rooms produced numerous fragments of hexagonal stone roof-slates that are probably late Roman in date. Nails would have fixed these slates to battens on a roof frame and long-shafted small or medium-sized nails would have fitted the indented holes in the slates’ narrow heads (large building nails would have broken the slates). Is it possible that the blacksmithing episode in the basilican hall was intended to produce the nails that would have been needed in the later refurbishment of the rear range of rooms and the tribunal, which, after the hall’s demolition, were re-roofed, either wholly or in part, with stone slates instead of recycled old terracotta tiles?

Shortly after this blacksmithing phase, and no earlier than 395, the hall of Caerwent’s basilica was systematically demolished and most of the fabric removed to be reused elsewhere, leaving a low mound of unwanted building debris where the nave and south aisle had been. A new hypocaust was inserted into the tribunal, heated from a furnace at the end of the old south aisle. The north aisle of the hall was not covered with demolition debris and it is possible that it served as a portico or veranda in front of the rear range of rooms (which now stood as a free-standing building). The floors in some of these rooms had been patched and relaid before being covered with accumulations of material, suggesting continued use for some time followed by gradual decay, not sudden destruction.

The hypocaust in the tribunal, on the other hand, was intentionally demolished probably at some point in the 5th century and, although the room remained occupied, it would appear that it was no longer a public space. The tribunal’s roof collapsed eventually and some of the upstanding walls also. The fact that all the modern buildings occupying the site in 1987 sat on the footprint of the rear range of rooms and the tribunal, often reusing Roman walls, demonstrates that the reduced basilica has been used in a variety of altered forms and functions since the end of its history as a civic centre in a Romano-British city.