The Jesse Window
The Jesse Window at Wells Cathedral is one of the most splendid examples of 14th century stained glass in Europe.
It dates from about 1340 and, considering its age, is still remarkably intact. Fortunately, the window has survived the vicissitudes of time and British history (narrowly escaping destruction during the English Civil War) and so what we see today is basically how medieval glaziers designed and created it and how our ancestors viewed it before us.
There have been sensitive repairs over the centuries, of course, and steps were taken during World War II to protect the Window.
The Cathedral embarked, however, on a major project to conserve the Jesse Window in 2011. The first phase saw the installation of external, protective iso-thermal glazing. The second phase tackled the detail conservation of individual panels of the Window.
Why was the Jesse Window in peril?
There has been growing concern over the past few years that the Window may deteriorate and be beyond repair unless urgent conservation work is carried out. Recent inspections have shown that some of the lead is bowing and needs attention and that some of the leaded panels of glass are bulging and loose. More significantly, the medieval glass is suffering the effects of condensation and consequent mould growth. This, in turn, is attacking the painted layers on the glass: the paint is peeling and the glass is suffering corrosion; consequently, the whole medieval structure is at risk.
The Cathedral’s solution
The Cathedral sought the advice and assistance of a team of the best medieval glass experts in the country, as well as an eminent German consultant conservator, Dr. Ivo Rauch, to inspect the window and advise on the best course of action to save it. A programme of monitoring, testing and analysis was undertaken over a two-year period, to assess environmental conditions inside and outside the window. A further fundamental element of the work to conserve the glass was, therefore, concentrated on providing a protective barrier to the exterior of the medieval window.
Fortunately, the design of the medieval tracery and stone dressings of the window is such that the insertion of the protective glazing will have little visual impact on the window and the Cathedral’s architecture. Conservation of the medieval glass can be undertaken with minimum intervention so re-leading is kept to a minimum to reduce the risk of damage to the precious glass. Careful cleaning was also be undertaken and loose paint layers consolidated both externally and internally.
The scaffolding was finally removed from the window in November 2014 revealing the unique beauty of this marvellous window for all to see.