I suppose you want to know how Cesare got here. I'll indulge you.
It was 1506. He was imprisoned in Castile. A sympathetic count smuggled in a rope, Cesare climbed out the window and dropped 70 feet, fracturing several bones, but his fall was broken by a servant who preceded him. Both the servant's legs were snapped and he was left to be captured and executed. Cesare escaped in merchant's clothing and chartered a small ship in Santander. He reached Navarre, the court of his brother-in-law. At the time, Navarre was dealing with upheavals secretly led by the Castilians. The King asked Cesare to command his army of 10,000. He was to retake Viana Castle from the Count of Lerin and the Castilians aiding him.
Excitedly, he wrote a letter to Lucrezia: "Once the Castle has been pacified, I will regain the support of the French and march back into Rome".