The Borgias by Alexandre Dumas — Read

Caesar was in prison for two years, always hoping that Louis XII would reclaim him as peer of the kingdom of France; but Louis, much disturbed by the loss of the battle of Garigliano, which robbed him of the kingdom of Naples, had enough to do with his own affairs without busying himself with his cousin's. So the prisoner was beginning to despair, when one day as he broke his bread at breakfast he found a file and a little bottle containing a narcotic, with a letter from Michelotto, saying that he was out of prison and had left Italy for Spain, and now lay in hiding with the Count of Benevento in the neighbouring village: he added that from the next day forward he and the count would wait every night on the road between the fortress and the village with three excellent horses; it was now Caesar's part to do the best he could with his bottle and file. When the whole world had abandoned the Duke of Romagna he had been remembered by a sbirro.

The prison where he had been shut up for two years was so hateful to Caesar that he lost not a single moment: the same day he attacked one of the bars of a window that looked out upon an inner court, and soon contrived so to manipulate it that it would need only a final push to come out. But not only was the window nearly seventy feet from the ground, but one could only get out of the court by using an exit reserved for the governor, of which he alone had the key; also this key never left him; by day it hung at his waist, by night it was under his pillow: this then was the chief difficulty.