In the spring of 1498 these barons, having issued victorious from their war with the Pope, began a bitter contest with their hereditary foes, the Colonna, which, however, ended in their own defeat.

These houses made peace with each other in July, a fact which caused Alexander no little anxiety, for upon the hostility of these, the two mightiest families of Rome, depended the Pope's dominion over the city; his greatest danger lay in their mutual friendship.

He therefore endeavored again to set them at loggerheads, and he succeeded in attaching the Orsini to himself,--which they subsequently had reason to regret.

He accomplished his purpose so well that they intermarried with the Borgias; Paolo Orsini, Giambattista's brother, uniting his son Fabio with Girolama, a sister of Cardinal Giovanni Borgia the younger, September 8, 1498.

The marriage contract was concluded in the presence of the Pope and a brilliant gathering in the Vatican, and one of the official witnesses was Don Alfonso of Biselli, who held the sword over the young couple.[63] Shortly afterwards, October first, Caesar Borgia set sail for France, where he was made Duke of Valentinois, and where, in May, 1499, he married Charlotte d'Albret, sister of the King of Navarre.