Pietro Torrigiano
Bust of Dr John Colet 1518

I was initially asked to examine this sculpture by Jane Ruddell, the archivist at Mercer’s Hall, because the room in which it was displayed was due to be refurbished. Visually the bust was in poor condition and it had been suggested that it might be possible to take a mould from the plaster so that a bronze could be cast from it and used to replace the original on display. The bust appeared to be 18th century in style, but Jane’s research had led her to suspect that it may be older. She requested an initial condition report to help decide whether the process of casting would cause any damage to the plaster.

The history of the bust is the subject of some scholarly debate and it is not entirely clear when it was first installed at the school. It is thought to be a copy made from a terracotta original attributed to the Florentine sculptor Pietro Torrigiano and was made to form part of a monumental tomb commemorating Colet in St Paul’s Cathedral. It therefore seems that there were two busts; one on the monument and one at the school. It is possible that the plaster was cast from the terracotta original but is not clear whether this process was carried out at the same time, or afterwards.

After my initial examination, and on the basis of some background research, we decided that it would be unwise to take a cast from the plaster and suggested instead that the original plaster could be cleaned and restored to improve its visual appearance. I also proposed that some analytical samples should be taken to see if it was possible to discover any more information about the history of this bust. Permission was then given to undertake restoration once all available information had been gathered from the surface.

The surface of the bust was dirty and marked with a number of small losses. There were also several cracks and old restorations visible. First samples taken from the surface suggested that there was a thin layer of paint on a preparatory layer, consistent with what might be expected from 16th or 17th century sculpture.

Our tests revealed that we would need to use a combination of methods to clean the surface but the preliminary cleaning removed a great deal of surface dirt and recent (post-1950) painted restoration in acrylic paint. At least four different programmes of restoration were revealed in all. Loose areas and old fills were consolidated where possible or replaced to improve structural strength.

Our observations suggested that there were two distinct types of plaster used in the body of the bust: one type was very white and homogeneous and was used to make the circular socle base. It was also applied at the back and over the lower edges of the cloak whereas the other type of plaster seemed to have been used for the underlying body and possibly for the head. The very white plaster is more similar to a modern gypsum plaster but the main body of the sculpture was more more heterogeneous and seemed to contain impurities such as clays and particles of soot. This would suggest an older form made before the 19th century and more akin to the traditional form of ‘stucco’. Based on this information the fact that the socle base is made in what appears to be a relatively modern white casting plaster implies that this part of the bust is a later addition and was perhaps added in a response to a change in fashion.

There was a thin continuous layer of a gesso-like substance over the entire body and head, but not on the socle base. Cleaning revealed small islands of dark paint that had been imperfectly covered by the gesso and we decided that it would be important to uncover and document these paint samples where possible so that we could take further samples for analysis. The samples were sent to Dr Spike Bucklow at the Hamilton Kerr Institute in Cambridge.

His analysis revealed that the islands were fragments of a much older surface finish comprising between four and ten successive layers of paint. This suggested that the polychromy on the bust was repainted on numerous occasions; sometimes involving a change of colour and effect, but largely alternating between reddish orange, brown and black. There is also a possibility that there may have been silver leaf applied to the front of the bust at some point. Overall, the analytical report concluded that the paint layers exhibited features that are not inconsistent with late medieval or renaissance polychromy. The upper painted layers appeared to be white, leading us to speculate that this was the point at which tastes changed to favour sculptures that were unpainted, under the influence of Neoclassicism around the late 16th century. Our analysis suggests that the bust was then painted over with a gesso layer and that the thin layers of paint detected in our first paint analyses may have been applied using a range of earth pigments as a kind of toning layer, possibly in a thin varnish or rabbit-skin glue to give the appearance of age to the white gesso layer.

The process of cleaning, consolidation and filling left the bust with a surface that was still visually patchy and damaged in a number of areas. The fills were retouched with acrylic paints and inpainting of the surface was carried out where necessary using an intervention layer to unify the appearance so that the bust was suitable for display in Mercers’ Hall, whilst retaining original surface and information beneath.

In the process of treating this sculpture a great deal of previously hidden information has been revealed that hints at a long and complex history and it now seems probable that the bust has been changed and adapted through a number of events, periods and styles. The evidence, combined with historical accounts of the bust’s history at St Paul’s School, seems to support the hypothesis that that the plaster bust was placed at the school as early as the 16th century and that, contrary to current opinion, the entire bust is largely original although heavily altered in parts. This would make the Mercers’ bust the earliest surviving example of this important sculpture and may be contemporary with the lost terracotta. It is hoped that more research in the archives of the Mercer’s Company and St Paul’s Cathedral might help to gather further information about the bust’s history.

With thanks to:

Jane Ruddell, archivist at Mercers' Hall, for all her help with this project

Tessa Jackson, sculpture conservator, for her assistance with the practical treatment

Dr Spike Bucklow, Senior Research Scientist at the Hamilton Kerr institute, for the analysis