A rare medieval painting may have escaped destruction by Protestants during the Reformation because its owner disguised it using the Ten Commandments, according to a spokesman for Cambridge's Fitzwilliam Museum.
The 500-year-old painting depicts Judas betraying Jesus and originally hung in a parish church. The Protestant Reformation saw many paintings and sculptures destroyed or defaced because they were believed to violate the commandment against the worship of images.
However, when the painting was at risk the owner appears to have turned it round and disguised it. The Fitzwilliam spokesman said: "16th century lettering was revealed using infra-red photography, proving the painting had been recycled at the time of the Reformation, the offending image turned around and the back converted into a painted board probably listing the 10 commandments, typical of a Protestant church furnishing."
Thousands of church paintings and sculptures – an estimated 90 per cent of Britain's stock of religious art – were destroyed in the 16th and 17th centuries.
The painting was purchased by the Fitzwilliam Museum in 2012 from the Church of St Mary in the Diocese of Peterborough. It had a "considerable layer of surface dirt, bat faeces and heavily discoloured varnish" which made it difficult to see the image in full.
Conservator Dr Lucy Wrapson said it was impossible to know who had painted the lettering onto the back but said the painting might have been "deliberately saved".
"The painting is fascinating, and conservation and cleaning has revealed the vibrant original medieval colours," she said, adding she "cannot stress how rare this is".
