Antonio Maffei

Father Antonio Maffei is one of the priests under the employ of Lorenzo de' Medici, under the supervision of Uberto Alberti. As such, he is in league with Alberti's treachery towards Lorenzo, and was one of the key proponents of the Pazzi Conspiracy against the ruling family of Florence.

Assassin's Creed: Lineage
Father Maffei's first appeared in the second part of Assassin's Creed: Lineage, after Giovanni intercepts a letter from the suspected conspirators of the murder of the  Duke of Milan in Venice, which was waxed with the Barbarigo family seal. As Giovanni shows the letter to Lorenzo and Alberti, the latter quickly realizes that the contents are encrypted with a strange code, and that translating it would take several hours. Alberti then hands the letter to Father Maffei to work on.

Later that night Father Maffei hands the complete translation of the letter to Alberti, who praises him for the good work and tells him to fetch Giovanni for his next mission. But before leaving the palazzo, Alberti warns the priest of dangerous secrets, and makes him a vow of silence, of not to tell anyone of the true contents of the letter. After fetching Giovanni from his residence and returning to the Medici palazzo, he is seen working on a duplicate letter, as Alberti claims they were "unable" to decode it, and hands the completed forged document for Giovanni to deliver to Rome.

After Giovanni's failure to capture Rodrigo Borgia, he returns to Florentine home as his wife tends to his near-fatal wound. Father Maffei then appears in front of the Auditore residence, with armed guards, demanding entry and custody of the Assassin. But Giovanni evades capture as his eldest son buys him enough time to slip into a hidden passageway.

Assassin's Creed II
Father Maffei is later seen in in the game as one of the Pazzi conspirators that Ezio assassinates in San Gimignano (DNA Sequence 5). He is located in one of the towers in town.