The Cathedral Vault

The view of the nave and quire vaulting from the west end of the cathedral is quite unforgettable. At 97.3m (319 feet), it is the longest continuous piece of medieval Gothic vaulting in the world and has been described as having the appearance of an avenue of palms.

The individual ribs of the vault are called tiercerons and the whole, a tierceron vault. Where the ribs intersect, the unsightly holes are plugged with carved stone bosses. The bosses also have a structural purpose: as keystones, locking the whole ceiling in place.  

There are over 400 carved bosses and sub-bosses in the cathedral and 34 of the massive carved corbels (the big stones that start above the nave and quire columns and continue upwards to where the vault ribs splay out) - together with much other carved stonework. All of these features, apart from their decorative function, help to support the vault and all were originally painted. 

The big central bosses weigh something over two tonnes, and the feat of lifting these and other massive stones the 21m (68 feet) to the nave vault using only very primitive mechanical help is almost incredible to 21^st century minds. 

The Gothic rebuilding of the cathedral started sometime after 1265 and the Lady Chapel vault, and those of the flanking chapels, were in construction in the 1280s; a great deal of imported limestone, from Caen in Normandy, was used in this. Other limestones (eg Portland stone, Beer stone) and easily worked sandstones (such as Ham stone and Salcome Regis stone) were used in the presbytery, the quire and the nave vaults.  

A series of inscribed rolls of vellum, stored in the Cathedral Archives and   which run from 1279 through to the completion of the rebuilding in1342 (there are some missing years), provides a detailed history of the Gothic reconstruction. Called the Fabric Rolls, they tell us the sources of many of the materials used in the reconstruction. There is also fine detail of who worked on this and how much they were paid for doing so.

The themes of both bosses and corbels throughout the cathedral are many and varied. The quality of the engraving of vegetation on some early bosses and corbels is outstanding.

Many bosses show identifiable creatures, mythical ones such as mermaids and dragons, and living creatures of many sorts. Other bosses and corbels depict biblical or apocryphal stories (the Crucifixion, Samson and the Lion, the Coronation of the Virgin etc), others, legends and folk tales; many show clerical or secular heads or figures who are anonymous to us. The best-known boss in the cathedral (in the nave) shows the assassination of Archbishop Thomas à Becket in 1170.

The first master mason of the cathedral whose name is known, Master Roger is mentioned in the Fabric Roll for 1297. Amongst subsequent architects, the best known was Thomas of Witney (master mason from 1316 to around 1342). Masons left a number of their marks in the vault.

A series of charming small corbels in the north and south transepts depicts cathedral labourers.

To make for the easier identification of a particular boss or corbel, a numbering system was introduced by Prideaux and Shafto in 1910.  

To see the vault at its best, visitors should come on a bright day and bring a good pair of binoculars with them. 

Print Page