The term 'SON OF VESPASIAN' can be summarized by the crossword solution of 'TITUS' (5 letters). Titus was the son of Roman Emperor Vespasian, who reigned from 69 to 79 AD. He was the first Roman Emperor of the Flavian dynasty and is remembered for his military campaigns and for his administrative reforms. Titus was an important figure in Roman history and is remembered for his successful reign as Emperor.