He first appears in The Assassins of Rome when he unexpectedly turns up at Jonathan's house. A former Sicari and now a slave in Corinth, he has been hired by Berenice to assassinate her rival 'Susannah the Beautiful', who he guesses is his sister. Determined to protect her from the two other assassins Berenice had hired, he journeys to Rome with Jonathan. After some misadventures, he is appointed steward of the Golden House by Titus. There, he falls in love with Rachel, Rizpah's mother, but before they can marry dies of the fever in The Enemies of Jupiter.
- The name 'Simeon' is of Hebrew origin and means 'God is listening'.