Count Girolamo de' Riari, accounted a nephew of Sixtus, was, like his elder brother Piero and Caterina his sister, a natural child of the Pope. The three were treated with parental affection by the pontiff, and had their home in his private apartments, being waited upon by their unrecognised mother in the guise of nurse and guardian. Piero de' Riari was created a Cardinal when a spoilt boy, and became, as a man, infamous for his debauchery and villainy. Sixtus had the effrontery to select him as successor to Archbishop Orsini in Florence, but his action was prompted by a motive, which was firmly fixed in his heart. This was nothing less than the supplanting of Lorenzo de' Medici by Piero or Girolamo! So far, however, as Cardinal de' Riari was concerned, Sixtus' ambitions were wholly disappointed by his sudden death, due to violent excesses of all kinds. Like his brother, Count Girolamo, the offspring of illicit lust, and brought up in the depraved atmosphere of the Papal court, was a reprobate; but Sixtus' vaulting ambition stopped not at character and reputation. He was bent upon the permanent aggrandisement of all the branches of the Delle Rovere family. Casting about for territorial dignity, the Pope set his heart upon the Lordship of Imola, where Taddeo Manfredi of Faenza, being in financial difficulties, had surrendered the fief to the Duke of Milan. The proposal to bestow the Lordship upon Count Girolamo de' Riari by purchase was warmly resented by the Florentines. Sixtus approached the question in a most underhand and suspicious manner. He knew perfectly well that negotiations were on foot for the acquisition of the property and title by Lorenzo, on behalf of the Florentine Government. Nevertheless he sent a secret mission to Galeazzo Sforza, Duke of Milan, offering the handsome sum of fifty thousand gold ducats, with a proviso, that the Duke should bestow the hand of his illegitimate daughter Caterina upon Girolamo. By way of adding insult to injury, Sixtus impudently sought a loan from the Medici bank, with which to pay the Duke: this greatly offended Lorenzo and all the leading men in Florence. What made the Pope's conduct more despicable, was the knowledge that he regarded this matter as the first step in a line of policy which aimed at supersession of the Medici by the Riari in the direction of Tuscan affairs--himself being Over-Lord. The Pope's demand was refused indignantly by Lorenzo, who, in the name of the _Signoria_, administered to his Holiness a severe rebuke for his interference in the affairs of Florence. The relations between the two Governments became strained, but Sixtus was perfectly indifferent to opposition where personal interests were concerned.