With its leafy walled garden, 13th-century porch and beautiful Cosmati work, this picturesque church is worth a quick detour. Of particular note are the 13th-century frescoes in the left-hand nave, including one of three naked girls in bed. Legend has it that these girls were saved from a life of prostitution by St Nicholas, who threw three stockings filled with gold up to their bedroom. St Nicholas is better known as Santa Claus and this story is the origin of the Christmas-stocking tradition.