This hospital founded in 1277 owes its name to a hollowed-out tree trunk which was used to receive the offerings. The elegant Renaissance portico in front of the facade was added in 1514. However it is its wonderful varnished terracotta frieze, from the studio of the last of the Della Robbia, Giovanni, that lend the hospital and Pistoia its greatest glory: in seven panels, it illustrates the seven Labours of mercy.