The Hidden Ones concluded that the ruler of the Roman Empire, Gaius Julius Caesar Augustus Germanicus, commonly referred to as Caligula, was a tyrant backed by the Order of the Ancients and the land had to be freed of him. On 24 January 41 CE, Leonius stabbed Caligula with a dagger in an underground corridor beneath Palatine Hill, killing him.
By the time of the Renaissance, a tomb dedicated to Leonius was located beneath Santa Maria della Visitazione in Venice, Italy. The Italian Assassin Ezio Auditore da Firenze explored the tomb and took the hidden seal from the tomb's sarcophagus, which later allowed him to obtain the Armor of Altaïr Ibn-La'Ahad sealed in the Sanctuary beneath the Villa Auditore in Monteriggioni.
- Historically the name of Caligula's killer was Cassius Chaerea.
- Assassin's Creed II (remains only)