Emilio Barbarigo

Uberto Alberti originally was a friend of Giovanni Auditore but was secretly a Templar and is killed by Ezio at the end of memory block two.

Uberto Alberti was the first assassination target and was the first to be killed by Ezio. Definitive proof that he was a Templar was when Rodrigo Borgia who was the leader of the Templars was seen in his house when Ezio deliverd a letter to him to prove that his father was innocent after he was arrested. It was by his hand that Giovanni and his sons died. But later Paula the courtesan leader had tracked Uberto down and gave Ezio  where he was. Soon after Uberto was assassinated Ezio fled Florence thus beginning Ezio's life as an assassin.