Maximus, assisted by Tavius, intended to kill Nero during a performance for him in Rome. However, a centurion learned of Maximus' intentions and hired Ascaris to assassinate him. Ascaris murdered Maximus as he made his way to Rome.
The First Doctor discovered Maximus' body and lyre. When he was discovered by the centurion, he claimed that he was Maximus, and was forced to continue the deception for the rest of his stay in Rome. (TV: The Romans)