cortegiania:

The Pazzi conspiracy in 1478 came as a rude shock to a carefree city. The Pazzi bank, in the course of a treacherous war in which the adversaries did not scruple to use the most devious methods, had taken the business affairs of the papacy away from the Medici. Sixtus IV, his nephew Riario, and Francesco Salviati, the archbishop of Pisa, supported the Pazzi and in the end formed a conspiracy with them. They decided to assassinate Lorenzo and Giuliano in the cathedral during Easter mass on April 26, while the archbishop was to take over the signoria (the council of government). Giuliano was indeed killed in front of the altar, but Lorenzo succeeded in taking refuge in a sacristy. [X]