Assassin's Creed 2 Episode 8: Wolves in Sheep's Clothing

"Knowing that the Pazzi had planned something involving the Medici, beginning at the Duomo, Ezio Auditore set out to stop them."
"After the failed assassination attempt on the Medici family, Francesco de' Pazzi led a group of his guards to take over the Palazzo della Signoria in order to gain control of the city. Lorenzo de' Medici, who survived the encounter, requested Ezio's assistance in killing Francesco."