After some meetings in the garden of S.Ambrogio, where they matured their plans, they laid their project of tyrannicide as a holy offering before the patron saint of Milan.[4] Then having spent a few days in poignard exercise for the sake of training,[5] they took their place within the precincts of S.Stephen's Church.

There they received the sacrament and addressed themselves in prayer to the Protomartyr, whose fane was about to be hallowed by the murder of a monster odious to God and man.

It was on the morning of December 26, 1476, that the duke entered San Stefano.

At one and the same moment the daggers of the three conspirators struck him--Olgiati's in the breast, Visconti's in the back, Lampugnani's in the belly.

He cried 'Ah, Dio!' and fell dead upon the pavement.