Claudius Marcus was the first Proconsul of the planet 892-IV, a civilization were the Roman Empire never fell. He gave R.M. Merik the power and position in order to help him lure other Starfleet crew to the planet to fight in the gladiator games.
He killed Merik in 2267, because Merik helped the USS Enterprise crew escape. (TOS: "Bread and Circuses")