Early in the game, you complete the mission Novella's Secret which takes you through the first of the game's six hidden assassin's tombs. The remaining five tombs are all optional. There were three tombs within the regions of Florence and Tuscany. This tomb was the resting place of Darius, who assassinated Xerxes I of Persia. Assassin Tombs To unlock the “Armor of Altair” set in the Sanctuary inside the Villa Auditore in Monteriggioni, you must collect six seals from the tombs of assassins long past. Assassin's Creed II - Assassin's Tombs Il Duomo - Florence The entrance to this Tomb is at the north end of the Basilica Santa Maria del Fiore. The first tomb you will visit is under the Santa Maria Novella during Sequence 4 as part of the main story. ". For Assassin's Creed II on the Xbox 360, a GameFAQs message board topic titled "can you re-enter Assassin's Tombs? There are six such tombs in Assassin's Creed II. The first was located within the catacombs of the Santa Maria Novella, and was discovered by the Assassin Ezio Auditore da Firenze in 1478, after eavesdropping on a Templar meeting.