The Legate (overall commander) of the Second Legion, Vespasian is based on the actual historical character by the same name. The son of a lower level member of the equestrian class, he does have great career and political ambitions, which cause him to take the common approach of entering the Legions in order to further his advancement within Roman political life.
Far from simply being an ambitious politician, Vespasian is portrayed as an extremely honorable man, and a solid, qualified military leader with an excellent grasp of tactics. He is also a very brave officer and tends to lead from the front, at great risk to himself. His personal beliefs in Stoicism cause him to specifically adopt a very professional, disciplined and rigid manner as the commander of Second Legion - which sometimes becomes a point of self-loathing and self-censure within himself, in instances where he realizes that he has made any departure from this professional demeanor. His concerns both for mission success as well as the quality/welfare of his men, are extremely high -and the problems that arise from balancing these oft-conflicting values are Vespasian's greatest struggles.