Byzantine Empire (yes, yes, I know it after the Roman Empire, but some people consider it a continuation) Basil I the First. Basil started off as a peasant. In an ASB world where gladiatorial combat is used for military training, he could have become a gladiator instead. Through murdering the right people at the right time, marrying the right woman at the right time (a gladiator and the emperor's daughter / mistress story) , and intrigues Basil becomes emperor. Basil the First then hires the Varangian Guard, his former Gladiator buddies, as his bodyguard.