Contendo

From the introduction:

Contendo is a roleplaying game aimed at giving players a chance to adventure through time, while solving mysteries and exploring the ancient world. The game’s setting is designed to emulate anywhere in the world during roughly anytime during antiquity. One day you might be part of Caesar’s military campaigns against Gaul, and the next day witness the death of Socrates. Later, your band of Iberian pirates may encounter a fleet of Numidian warships and end with an epic naval showdown. The strength of Contendo is its ability to be edited. Game masters can change rules as they see fit, and the players can create their own traits, backgrounds, and custom character options for whatever scenario they wish.