Today, only three medieval mosaic pavements survive in England: one in Canterbury Cathedral and two in Westminster Abbey, associated with the shrines of St Thomas Becket and St Edward the Confessor respectively. While they are well known and frequently mentioned in antiquarian writings and by modern scholars, though, none of the pavements had been subjected to detailed archaeological study until a major conservation project was undertaken on the sanctuary mosaic at Westminster in 2008-2010. This was accompanied by archaeological recording, which not only revealed much about the construction of the pavement in 1268, but also illuminated subsequent repairs and alterations to its design.
When conservation was complete, we set about writing a monograph on the pavement, and enlisted David Neal to assist with its illustration – but the sanctuary pavement at Westminster was not an isolated artefact. It was, in fact, only part of a rich ensemble of Cosmati mosaics that included a second pavement in the shrine chapel, the shrine pedestal of St Edward, and the tombs of Henry III and his grandson, John of Windsor. This dazzling display of Italian mosaic work, named after a Rome-based family of specialist artisans, was initiated and overseen by Henry III between c.1260 and his death in 1272; one further tomb-cover was added in 1274 for Henry’s daughter-in-law, Aveline de Forz.
The whole Cosmati assemblage was published in two volumes in 2019 (and discussed in CA 359), and a key part of our analysis of the Westminster pavements and monuments was that certain elements of their design reveal that the Cosmati mosaicists must have worked previously in England. They clearly knew about certain materials that were already available and being used by masons here, notably Purbeck marble and white Lias limestone, which were employed as substitutes for Mediterranean marbles. Since Henry III never travelled to Italy, he could not have seen Cosmatesque mosaics there, and the popular myth that Abbot Ware was the initiator of this monumental and vastly expensive scheme of decoration has no credibility. Instead, Henry must have seen Cosmatesque work somewhere closer at hand. I suggested that Canterbury may have provided his source of inspiration.
Canterbury’s opus sectile (made of cut and shaped pieces of stone, rather than small tesserae) pavement lies in front of the Shrine of St Thomas in the Trinity Chapel. David Neal had drawn it in 2015, and we had included an image of it in our Westminster monographs for comparison. At that time, we stated that it was clearly not a product of the Cosmati mosaicists, and there the matter rested – until 2020, when David urged that we should publish a description and analysis of the pavement. Carrying out a major study of the mosaic and other pavements in the Trinity Chapel at Canterbury had never been on my ‘to do’ list, but the advent of the COVID-19 pandemic changed things somewhat. With time on our hands, David and I – working from our separate isolations, and making periodic visits to a near-empty Canterbury Cathedral – found ourselves being drawn into a two-year research project, the results of which have just been published (see ‘Further reading’ at the end). In this issue of CA, I will explore some of our conclusions about the mosaic, and next month I will cover our findings concerning the shrine chapel itself.
To set the scene: most commentators have accepted that the opus sectile pavement dates from c.1182-1184, when construction of the shrine chapel began, following the murder of Archbishop Becket in 1170 and his canonisation three years later. (See CA 376 for more on the veneration of St Thomas at Canterbury, and CA 364 to read about recent archaeological research within the cathedral itself.) A few scholars have, however, opined that the pavement might incorporate elements of an earlier mosaic, salvaged from elsewhere in the cathedral. Detailed study of the mosaic and petrological identification of its materials by Kevin Hayward has also revealed a complex history of repair and alteration. One thing was clear: the mosaic certainly did not originate in the Trinity Chapel.
Given our project’s origins in the early days of the pandemic, it seems appropriate that the pavement’s historical context reflects a time when England’s population was under severe restrictions. King John (r. 1199-1216) had incurred the wrath of Pope Innocent III by rejecting his choice for the new Archbishop of Canterbury, and in 1208 Innocent responded by placing the whole of John’s kingdom under papal interdict. This was a drastic step that saw churches closed, the Mass and most sacraments suspended, and burials within consecrated ground banned. Coincidentally, the interdict came into force on 23 March, the same date as our first lockdown was announced – though it endured rather longer, being lifted only in 1214 when John finally agreed to the Pope’s demands.
Like many leading churchmen, Canterbury’s prior and monks had been exiled abroad during the interdict, travelling to St Omer, where they were evidently inspired by the figurative roundel pavements in the cathedral and abbey. After their return, they commissioned French artisans to construct a similar pavement to embellish the ceremonial approach to Becket’s shrine from the west. This was installed in c.1215, boasting 48 mastic-inlaid roundels depicting labours of the months, signs of the zodiac, virtues conquering vices, and mythical beasts, though they do not all survive today. When the opus sectile pavement was moved to that same location, it necessitated the displacement of half of the roundels. As we will explain below, the reconstructed mosaic did not arrive in its current location before the early 1230s. So, where did it come from?
To answer this, we have to go back to the late 11th century, when Anselm, a scholarly and wealthy Italian nobleman, was consecrated Archbishop of Canterbury in 1093. He instigated the construction of a huge new eastern arm to the cathedral, later dubbed Anselm’s ‘glorious quire’. It had many Italianate features, and in 1124 William of Malmesbury marvelled at its ‘pavements’. These probably included a second opus sectile pavement, now lost, as indicated by a small section of mosaic filling a gap in later paving. The plan of Anselm’s quire and presbytery was convincingly reconstructed in 1844 by the Reverend Robert Willis – the ‘grandfather’ of church archaeology – using remarkably precise descriptions by a 12th-century chronicler, Gervase of Canterbury. Slight modification is now necessary, however, in the light of recent research.
A mobile mosaic
The central part of the surviving mosaic pavement is clearly Romanesque in style, and dates from the early 12th century. The mosaicists who created this were so highly skilled that no mortar is visible between individual tesserae, many of which are of purple and green porphyry, which is extremely hard to cut. A pavement of such magnificence must surely have lain in front of the high altar, where Becket’s corpse, dripping blood, rested on a bier overnight on 29/30 December 1170. Through this intimate contact, the mosaic became a secondary relic.
Canonisation swiftly followed, as did hordes of pilgrims, but there was no suitable location in which to create a grandiose shrine-chapel to accommodate them. The problem was conveniently solved in 1174 by a conflagration (surely arson) that destroyed Anselm’s quire, clearing the way to construct the present Trinity Chapel. The damaged mosaic was left in situ, in anticipation that the sanctuary would be restored and the relationship between the high altar and pavement remain unchanged. Meanwhile, further east, construction of the new Trinity Chapel and Shrine of St Thomas proceeded slowly, from 1182 until their dedication in 1220.
The chapel was raised over a lofty crypt, and to reach the shrine from the sanctuary required a flight of 18 steps, to cope with the differential between their respective floor levels. This gave rise to the monumental stone staircase that is such an impressive feature of Canterbury Cathedral today, but its construction spread across the site of the high altar and half of the mosaic. To resolve this, an intermediate landing was created in the stairway, on which to elevate the altar over its original site, but the mosaic had to be lifted and repositioned. That is when the French roundel pavement in front of the shrine was partly destroyed and the modified mosaic installed. It was reduced in size to suit its new location, and some of the outer panels were entirely reconstructed, but in 13th-century Cosmatesque style, not Romanesque. We therefore conclude that Cosmati mosaicists from Italy had been hired to disassemble and reconstruct the pavement, shortly before Henry III was married in the cathedral in 1236. The great flight of steps must have been installed, and the sanctuary restored, prior to that event.
Henry was already familiar with the cathedral, having been a frequent visitor to Canterbury since 1220, when he was present for Becket’s enshrinement; he possibly saw the fire-damaged mosaic in situ. Later, he may well have witnessed the Cosmati mosaicists carrying out the reconstruction of the pavement. Henry would undoubtedly have visited Becket’s shrine on the occasion of his marriage, when he could not have avoided seeing the re-sited pavement, and he would have seen it again on every subsequent visit to the shrine. Perhaps he also visited St Augustine’s Abbey in the same city, where many tesserae from destroyed Cosmatesque mosaics have been found in excavations. In this light, there can be little doubt that Henry’s inspiration in the 1260s to adorn his new abbey at Westminster with sumptuous mosaics originated at Canterbury. It was there, too, that he would have seen English Purbeck marblers working side-by-side with Italian mosaicists. The same later happened at Westminster.
What of the pavement’s design? The 12th-century framework containing the mosaic essentially comprised four concentric squares, two of which are poised. Set between the innermost squares is a quatrefoil, and there is also a quartet of large rings, overlaid by the second and third squares. As for materials, the framework is entirely of Purbeck marble, which dates from the time of re-laying the pavement; almost certainly, cream Marquise limestone had been used in the original construction, as it was for the cathedral floors generally in the earlier 12th century (Purbeck marble paving was unavailable until the 1170s). The outermost square, forming the border, was discarded when the pavement was repositioned, allowing the design to sit more harmoniously amid what remained of the pre-existing roundels.
The original palette of materials employed for both the Romanesque tesserae and the slabs of opus sectile comprised purple porphyry from Egypt, green porphyry from Greece, white Carrara marble from Italy, black Tournai marble from Belgium, and pale grey Thassos marble from Greece. Most unusually, many of the mosaic panels are individually edged with thin strips of latten (brass): some are 19th-century replacements, but others are certainly primary. All are now tarnished and obscured by floor-polish but, like medieval funerary brasses, these fillets would originally have been gilded. The narrow bands of mosaic in the borders were also subtly elaborated by combining latten fillets of three different thicknesses.
Another embellishment seen in the pavement is drilling and pelleting. The technique involved drilling small holes into the surface of a tessera or a slab of marble to a depth of a few millimetres, and then plugging the void with a pellet of differently coloured marble. This form of decoration, known from Romanesque sculpture, is not found in Cosmatesque or Roman mosaics, but in the shrine pavement it had been applied to the black and white marbles, and is mainly visible in the better-preserved elements in the central area of the pavement. Four different sizes of pellet are present, ranging from 2mm to 9mm in diameter, and evidence for about 800 settings survives. The effort involved in drilling hundreds of small holes and making as many pellets to fit them was prodigious. Above all, the use of prestigious marbles, the precision fit of the tesserae, the framing of design details with gilded latten fillets, and the extensive pelleting, all proclaim this Romanesque mosaic to have been of truly outstanding quality, and potentially unparalleled by any other pavement laid in Roman or medieval Britain.
David S Neal and Warwick Rodwell (2022) Canterbury Cathedral, Trinity Chapel: the archaeology of the Mosaic Pavement and setting of the Shrine of St Thomas Becket (Oxbow Books, ISBN 978-1789258417, £80)
Warwick Rodwell is Consultant Archaeologist at Westminster Abbey.
ALL IMAGES: courtesy of Warwick Rodwell, unless otherwise stated