Rumpole asks the expert witness to confirm that the artist Taddeo diBartolo is "a Sienese master of the 14th century", and the expert replies, "Il Quattrocento." In fact the Italian term, which is used by art historians, refers to the 1400s, which is the 15th century rather than the 14th. It isn't clear whether the expert is correcting Rumpole or agreeing with him.