That Leo did not do more to check the tendency toward heresy and schism in Germany and Scandinavia is to be partially explained by the political complications of the time, and by his own preoccupation with schemes of papal and Medicean aggrandizement in Italy.
And Venice was ruled by a close oligarchy; Florence was passing from the hands of her oligarchs into the power of the Medicean merchants.
His own family was fortified by the marriage of his daughter to a son of Innocent VIII., which procured his son Giovannis elevation~to the cardinalate, and involved two Medicean papacies and the future dependence of Florence upon Rome.
In 1527 he joined in the movement for the expulsion of the family and was instrumental in defeating the Medicean troops under Cardinal Passerini, who were attacking the Palazzo della Signoria.
Thus Pizigano's map of 1367 extends as far east as the Gulf of Persia, whilst the Medicean map of 1356 (at Florence) is remarkable on account of a fairly correct delineation of the Caspian, the Shari river in Africa, and the correct direction given to the west coast of India, which had already been pointed out in a letter of the friar Giovanni da Montecorvino of 1252.
The system of the catasto, which led to abuses, was abolished, and a progressive income-tax (decima scalata) was introduced with the object of lightening the burdens of the poor, who were as a rule Medicean, at the expense of the rich; but as it was frequently increased the whole community came to be oppressed by it in the end.
Various plots against him were hatched, the anti Medicean faction being called the Del Poggio party because the house of its leader Luca Pitti was on a hill, while the Mediceans were called the Del Piano party because Piero's house was in the town below; the other opposition leaders were Dietisalvi Neroni and Agnolo Acciaiuoli.
He was refused admittance to the palace, and the people began to shout "Popolo e liberta I" in opposition to the Medicean cry of "Palle, Palle !"
The Ottimati were mostly anti-Medicean, and by 1527 the position was untenable.
Who desired an oligarchy, the Palleschi or Mediceans who generally supported them, the Adirati who opposed Capponi for his moderation, the Arrabbiati who were strongly anti-Medicean, and the Popolani who opposed the Ottimati.
Carducci made preparations for a siege, but a large part of the people were against him, either from Medicean sympathies or fear, although the Frateschi, as the believers in Savonarola's views were called, supported him strongly.
Baccio Valori, a Medicean who had been in the imperialist camp, now took charge, and the city was occupied by foreign troops.
Francis Hyett's Florence (London, 1903) is more recent and compendious; the author is somewhat Medicean in his views, and frequently inaccurate.
The Arrabbiati and the Medicean faction merged political differences in their common hatred to Savonarola.
The plague ended, Florence was plunged in fresh troubles from Medicean intrigues, and a conspiracy for the restoration of Piero was discovered.
The Medicean party lifted up its head.
After finishing the Principe, Machiavelli thought of dedicating it to one of the Medicean princes, with the avowed hope that he might thereby regain their favour and find public employment.
Leo's name is generally associated with the idea of the Medicean era as a golden age of science and art.
But, though illuminated by the rays of art, and loaded with the exuberant panegyrics of humanists and poets, the reign of the first Medicean pontiff, by its unbounded devotion to purely secular tendencies and its comparative neglect of the Church herself proved disastrous for the See of St Peter.
Among these was the grand-duke of Tuscany (Ferdinand II.), who took away some works and a portrait to adorn the Medicean library.
This post he resigned in 1534 on the election of Paul III., preferring to follow the fortunes of the Medicean princes.
In 1527 he had been declared a rebel by the Signoria on account of his well-known Medicean prejudices; and in 1530, deputed by Clement to punish the citizens after their revolt, he revenged himself with a cruelty and an avarice that were long and bitterly remembered.
To plead loyalty or honest political conviction in defence of his Medicean partianship is now impossible, face to face with the opinions expressed in the Ricordi politici and the Storia Fiorentina.
Henry II.'s queen was Catherine of the Medicean family; and her children, Charles IX.
Probably also his exclusive belief in experimental methods, and slight regard for mere authority whether in science or art made the intellectual atmosphere of the Medicean circle, with its passionate mixed cult of the classic past and of a Christianity mystically blended and reconciled with Platonism, uncongenial to him.
Years had healed the breach between him and the Medicean family; and on the occasion of the Pazzi conspiracy against the life of Lorenzo de' Medici, he had sent violent letters of abuse to his papal patron Sixtus, denouncing his participation in a plot so dangerous to the security of Italy.
Giovan Gastone was the last Medicean grand duke; being childless, it was agreed by the treaty of Vienna that at his death Tuscany should be given to Francis, duke of Lorraine, husband of the archduchess Maria Theresa, afterwards empress.
His discovery of the "Medicean Stars" was acknowledged by his nomination (July 1610) as philosopher and mathematician extraordinary to the grand-duke of Tuscany.