Moreover, the defenders had cause to fear treachery within their gates, for a paper had been picked up out of the moat containing an offer of terms of surrender.

It had been shot into the castle attached to an arbalest-bolt, and was intended for the castellan Castagnini.

This Castagnini was arrested, thrown into prison, and his possessions confiscated, whilst the Council placed the citadel in the hands of four of its own members together with Gianevangelista Manfredi--Astorre's half-brother, and a bastard of Galeotto's.

These set about defending it against Cesare, who had now opened fire.

The duke caused the guns to be trained upon a certain bastion through which he judged that a good assault might be delivered and an entrance gained.
Night and day was the bombardment of that bastion kept up, yet without producing visible effect until the morning of the 20th, when suddenly one of its towers collapsed thunderously into the moat.
Instantly, and without orders, the soldiers, all eager to be among the first to enter, flung themselves forward in utter and fierce disorder to storm the breach.