the chapel, which was dedicated to saint peter, was re-dedicated to "our lady of the common people" and to her honour a magnificent ancient altarpiece by coppo di marcovaldo, dating from about 1280 was put into place. because this image of the virgin mary was said to work miracles, many hundreds of candles were lit in front of it which soon stained the frescoes so that their bright colours could no longer be seen. eventually the painting was moved to a different church. then part of the roof fell in and had to be replaced. more damage was done in re-decorating. in 1680 the marquis francesco ferroni decided that the paintings were too old-fashioned and should all be pulled down. luckily the grand duchess vittoria della rovere stopped this from happening. in 1734 a painter called antonio pillori cleaned the frescoes. then in the 1770, there was a fire in the church, causing worse staining and some damage to the frescoes. (luckily the precious altarpiece had been moved.)