War Drums: The Story of Zanviet Arbuhnot 

In Britana, Rome has taken over the land. A Celtic warrior named Zanviet is captured by the Romans and is taken to Gaul. There he is transferred to Rome as a slave and is bought by a person who trains gladiators. He fights in the Colosseum and has his victory making roman emperor Julius Caesar notice him.  A man named Brutus comes along and asks him to join the plan of assassinating Caesar. During the assassination he is the last one to stab Caesar.