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Cathedral Mosaics

Only a small part of the Cathedral has yet received its mosaics - seven of the twelve chapels, the great sanctuary arch and the smaller arch in the crypt, together with a few panels elsewhere. Yet already over 12 million pieces of mosaic have been laid. To complete the decoration in the manner originally intended - as illustrated in the 1950 artist’s impression at the back of the Cathedral - would require up to a hundred million pieces.

Mosaic consists of small pieces of stone, marble, terracotta or glass (tessarae) applied to a prepared surface. When the practice first began is unclear but by the 4th century BC coloured pebbles were being used by the Greeks to produce regular patterns and representations of human figures and animals. The Romans used mosaic extensively for floors and in the first century BC they began decorating the walls of their imitation grottoes with marble chips, sea-shells and ultimately stone and glass tessarae.

In the first century AD the use of decorative coloured glass on walls increased but it was the Christians who applied the technique most extensively and successfully - culminating in the 5th and 6th centuries in the churches of Constantinople and Ravenna, and in the 12th and 13th in those of Palermo and Monreale in Sicily and St Mark’s in Venice.

The opaque glass tessarae used in the Cathedral average one square centimetre and come mainly from Venice and the Island of Murano nearby. Some have gold or silver leaf fused onto clear glass with another thin sheet of glass on top to protect the metal from the atmosphere. On average 700 tessarae are used to the square foot, so the blue sanctuary arch mosaic consists of over a million pieces and the Lady Chapel has about three million pieces. The first mosaics were designed for the Holy Souls Chapel by the artist W C Symons and it was only here that the Cathedral architect, J F Bentley, played a direct part, urging that a simple Greek style should be adopted and designing two wreaths himself.

The mosaics of the Holy Souls above the altar portray the journey of the souls through purgatory, where the archangels Raphael and Michael stand, to Paradise at the top. On the opposite wall are the three youths in the burning fiery furnace, while Adam and Christ are portrayed on the side walls. The mosaics were laid over eighteen months from June 1902 by 26 young ladies from the Oxford St Studio of George Bridge, who were based in Mitcham, Surrey. The tessarae are of irregular shape and predominantly silver in colour, the effect being toned down by salmon-tinted cement and wide joints.

The direct method was the one adopted. In this full-size coloured cartoons of the designs are transferred or traced onto the working surface. The tessarae are then inserted directly into the fixing medium, using the cartoon as a guide to positioning and colour.

Bentley was not concerned whether the fixing medium was water or oil-based (which allows more time for adjustment before setting), providing it was durable and the tessarae were worked in situ on the walls. In fact oil based mastic was used. Some sections were prepared in advance - face downwards on canvas in the studio, but the method was judged not to be a success. The advantages of the more traditional direct method are precision, the glittering effect of tessarae inserted individually and thus at different angles to the light, and the difficulty of judging the effectiveness of a mosaic in terms of colour and perspective when it is directly under a bright light (and possibly upside down) in the studio, rather than high on the wall or vault and dimly lit from below.

The direct method was the one used in antiquity though prefabrication did sometimes occur when working on very detailed designs. One way of doing this is to assemble the tessarae face upwards in a bed of damp sand, then overlay them with gummed canvas or paper, brushing out any remaining sand before inserting them in the fixing medium on the vault or wall. The paper or canvas is then moistened and removed. The reverse method, disliked by Bentley and tried unsuccessfully in the Holy Souls, is to assemble the tessarae face downwards onto gummed, full-size reverse cartoons. When set, the tessarae attached to the cartoons are hammered into place with wood block and mallet, the cartoons subsequently being removed to reveal the design (now face up), below.

The reverse method, referred to at the time as ‘the modern Italian method’ was used in the Chapel of St Gregory and St Augustine, across the nave from the Holy Souls. The designer was J R Clayton of Clayton and Bell, famous for its ecclesiastical stained glass, and the English Lady Artists carried out the mosaic work from December 1902 to May 1904, using rectangular, close-jointed, gold tessarae set with almost geometrical precision. Both here and in the Holy Souls, opus sectile - larger pieces of painted glass, cut to shape, - was used for the altarpieces. This is because, except when very small tessarae are used, mosaic is less effective to the eye at close range.

Bentley’s successor, J A Marshall, designed the next mosaics - the blue and gold flower-like pattern for the lining of the baldacchino (1906) and the simple but effective red and gold decoration of the Shrine of the Sacred Heart (1911), though this was replaced by James Powell and Sons in 1916. The direct method used here was also used by Robert Anning Bell for the altarpiece and blue niche mosaics in the Lady Chapel. Gertrude Martin was the mosaicist here in 1912-13. George Bridge's group of mosaicists also executed W C Symons’ design of St Edmund blessing London in the crypt and the less successful portrayal of St Joan of Arc in the north transept (1910-11).

Meanwhile the 4th Marquess of Bute had chosen Robert Weir Schultz, a Byzantine scholar, to organise the decoration of St Andrew’s Chapel, which the Marquess was funding. The mosaic designs, in the traditional Byzantine style, were prepared by George Jack. Above the altar and crucifix they show the Cross of St Andrew and his last prayer, while the saint and the story of his life appears on the wall opposite. The side walls show Bethsaida (his birthplace), Constantinople (where he was Bishop), Patras (his place of execution), St Andrews in Scotland (which has a relic) and Amalfi and Milan where his remains lie, taken from Constantinople by the Crusaders in l204. The tessarae were laid in 1913-15 by six of Ernest Debenham’s mosaicists, including a Venetian, under the direction of Gaetano Meo. Particularly effective is the glittering vault, with its fish-scale (or cloud) pattern and the birds in the arches.

Cardinal Bourne, who had succeeded the Cathedral’s founder (Vaughan) in 1903, had chosen Robert Anning Bell to design the first mosaics in the Lady Chapel and the sober tympanum above the main entrance, put up in 1916. But in neither case was he satisfied with the result.

He then turned to the artist Gilbert Pownall and established a school of mosaics under Basil Carey-Elwes in the Cathedral tower. From 1930 three English mosaicists, to be joined by two Venetians a year later, used the direct method to execute Pownall’s designs in the confessional recess (1930), the sanctuary arch (1932-33), St Peter’s Crypt (1934) and the Lady Chapel (1930-35). Work on another design was underway in the vault of the apse when Bourne died in early 1935, but in response to an organised campaign of criticism of Pownall’s designs, Bourne’s successor, Cardinal Hinsley, agreed to abandon the work and the apse mosaic was subsequently removed.

Twenty years went by before major mosaic work was again undertaken, though a panel depicting Christ the Healer, a memorial to the men of the Royal Army Medical Corps designed and executed by Michael Leigh, went up in St George’s Chapel in 1952. Four years later Boris Anrep, a Russian-born artist who had designed and executed the unfinished vault mosaic in the inner crypt in 1914 and that of St Oliver Plunket outside St Patrick's Chapel in 1924, was commissioned in 1956 to decorate the Blessed Sacrament Chapel. He chose a simple, early Christian style, a pink background and the reverse method. Full-size coloured cartoons were made in his Paris studio, tessarae from Angelo Orsoni selected and attached to working drawings in Venice and the results crated and sent to London. Peter Indri undertook the fixing in 1960-62 but the work was closely monitored and constantly adjusted by Anrep and his assistant, Justin Vulliamy.

Vulliamy also designed the mosaic of St Christopher in the nearby aisle niche but Aelred Bartlett designed that of St Nicholas opposite (1961) together with the mosaic lining the arches between the nave and transepts. Anrep and Vulliamy also worked closely together on the decoration of Paul’s Chapel which followed, but this time Anrep (by now over eighty) assisted Vulliamy and designed the principal figures, though in the event he disliked the final result. Again the indirect method was adopted and Peter Indri did the fixing in 1964-65.

Seventeen years later a smaller mosaic went up above the unused north-west entrance door. Designed by Nicolete Gray, it commemorates the 1982 visit of Pope John Paul II and was put in place in June of that year. Translated, the Latin inscription reads "May this door be the gateway of peace, through Jesus Christ who called himself the gate".

The mosaicist for the north-west door mosaic was Trevor Caley. In 1999 he returned to install a mosaic panel of St Patrick in its position to the left of St Patrick’s Chapel. The predominantly green mosaic was designed and executed by him on board in the studio using unglazed ceramic and traditional glass tessarae from Cathedral stocks, which provide a glittering effect in the light. Two years later another panel was installed. Between St George’s and St Joseph’s Chapels, it depicts St Alban, an early Romano-British Christian martyr. Round his neck is a red line symbolising decapitation. Designed by Christopher Hobbs it was produced on board in the studio and installed by Walter Bernadin and Tessa Hunkin of London Mosaic Workshop.

Work is currently underway to decorate St Josephs’s Chapel and the Vaughan Chantry. St Joseph’s now has a representation of the Holy Family in the apse above the altar, and the chapel is to be completed with a woven gold pattern for the vault and a depiction of craftsmen building the Cathedral on the west wall opposite - a reminder that St Joseph is the patron saint of workers. The designer is again Christopher Hobbs and the mosaicists London Mosaic Workshop, who will assemble the tessarae and prepare the mosaics in the studio. The Vaughan Chantry is dedicated to St Thomas Becket and the saint is depicted standing before the old Canterbury Cathedral on the east wall, while the west shows his murder. The mosaic was completed in 2005

Patrick Rogers

First published in Oremus the magazine of Westminster Cathedral February 1999.

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An artists impression of the Cathedral
complete with mosaic decoration.


St Paul as seen on the tympanum
mosaic above the sanctuary.


Image of the Priest, Melchizadek, in the
Blessed Sacrament Chapel.


Mosaic decoration of St Paul's Chapel by Boris Anrep.

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