Ferdinando II took over as Grand Duke of Tuscany to his father Cosimo II in 1621, at only eleven years. Effective power was exercised, until the age of majority, by a regency of which mother Maria Magdalena of Austria (1589-1631) and grandmother Cristina di Lorena (1565-1636) were part of it.
Ferdinando, like his predecessors, implemented a policy of balance with the great powers; the only exception was the clash with the Papal State. In the 1930s, the Duchy of Urbino, on which the Grand Duke advanced due to his marriage to Vittoria della Rovere, heir of the last Duke of Urbino, was the one to put the opposite interests into shock. This clash with Pope Urban VIII must also be kept in mind to better understand the difficulties that Ferdinand encountered in defending Galileo, when he fell into disgrace with the pontiff. The disagreements with Urban VIII did not cease later; on the contrary, they went to deepen in the forties, for the Pope's attempt to remove the Duchy of Parma from the Farnese. The interference led Ferdinand II to form an alloy with Venice and Modena and to clash with the pontiff in the war of Castro, who had neither winners nor losers.
In the government Ferdinand II was assisted by his brothers, to whom he was always very close, and to whom he delegated part of his duties: Mattias was in charge of military affairs, Giovan Carlo of Finance, Leopold of some political issues. He proved to be a good ruler, particularly in times of danger, as in the plague years of 1629-1631: in addition to promulgating important laws of public health, he himself used to travel around the city, showing himself among the people to help and encourage it.
The events of the trial of Galileo are linked to the name of Ferdinando II, celebrated in 1633 and ended with the condemnation and abjuration of the. The Grand Duke had been a disciple and protector of Galileo and, although he could not oppose the demands of the Holy Office - it must be remembered that at the time he was only 22 - he tried to lighten him as much as possible during the months of his forced stay in Rome. He put at his disposal the litter who led him to the papal capital and the lodging at the residence of the Tuscan ambassador. He arrived among the first to find him in his stay in Siena and, even after his return to Florence, he proved to hold him in high esteem by visiting often at the Villa di Arcetri, in which Galileo had been confined.
In the previous years the Ferdinand II trial had given ample credit to its Mathematical and Philosopher Primary. On more than one occasion he had consulted him to give his opinion on important engineering works: examples are the reports prepared on the arrangement of the Bisenzio river, to contain its continuous overflows, or about the project to make the Arno navigable, an enterprise that appeared to Galileo "pharaonic". He wrote in this regard in his analysis: "when they could put to work, as they could in immense establishments ancient lords of vast kingdoms, hundreds of thousands of slaves, I would not think of putting myself to the task and I would hope happy outcome" ( Ed. Nation, Volume VI, page 653). There was no shortage of requests for opinions on some projects for the construction of the facade of the Duomo.
With Ferdinando and his Corte Galileo he had very close relations, more than with all his predecessors, mainly thanks to the position of prestige consolidated over the years and secondly because the cultural interests of the Grand Duke were deeply in tune with those of the ancient master.
Ferdinando is remembered by his contemporaries as a man of culture and science. At Palazzo Pitti he personally conducted research in his "Experimental Medical Academy". He improved the thermoscope conceived by Galileo by adding some stairs, he delighted in meteorology, participating in experiments in measuring the humidity of the air through condensation hygrometers, he experimented with a sort of artificial incubator to give birth to the chicks in the citrus greenhouse of the Boboli Gardens, thanks to the new thermometers, to the set-up of which he had collaborated. He unconditionally supported the activities of the physician Francesco Redi and shared his interests.
In 1657, at the initiative of his brother Leopoldo and his, the Accademia del Cimento was born, a cultural project, but also a political one. The Medici, in fact, had invested for more than twenty years on Galileo and the Academy presented itself as a way to bring out the new experimental method, not directly affected by abjuration, from a viewpoint, however, conciliationist and non-antagonist to the Aristotelian theories sustained by the Church, and to the detriment of the greater revolutionary influence of Galileo's philosophy, the idea of interpreting natural phenomena according to mathematical and geometrical laws. The operation proved difficult and ultimately ineffective: the moderate and radical soul of the Academy came to the clash, with the loss of prominent figures such as Giovanni Alfonso Borelli, who abandoned the common work with barometers, thermometers, hygrometers, scales hydrostats, liquids exposed to frost and metals to heat, to focus solely on anatomical studies. After ten years the Academy was dissolved, without ever having taken a position on the causes of the phenomena, so meticulously cataloged and accurately described in the essays of natural experiences (Florence, 1667), the only work produced by the variegated assembly of scholars.