Italian nobleman who ruled as grand duke of Tuscany from 1621 to 1670. He was the eldest son of Cosimo II de’ Medici and Maria Maddalena of Austria. His 49-year rule was punctuated by the beginning of Tuscany’s long economic decline. He married Vittoria della Rovere, a first cousin, with whom he had two children who reached adulthood: Cosimo III de’ Medici, his eventual successor, and Francesco Maria de’ Medici, Duke of Rovere and Montefeltro, a cardinal.
Ferdinand, like his paternal grandmother Christina before him, was a patron, ally, and friend of Galileo Galilei. Galileo dedicated his Dialogue Concerning the Two Chief World Systems to him. This work led to Galileo’s second set of hearings before the Inquisition. Ferdinand attempted to keep the concerns of the Holy See from leading to a full-fledged hearing and kept Galileo in Florence until December 1632, when the Roman Inquisitors finally threatened to bring Galileo to Rome in chains if he would not come voluntarily. In June 1633, the Roman Inquisition convicted the astronomer for “vehement suspicion of heresy” and sentenced him to imprisonment for life. After this was commuted to house arrest, the devoutly Catholic Ferdinand welcomed Galileo back to Florence.
The first calamity of Ferdinando’s reign was an outbreak of the plague that swept through Florence in 1630 and took 10% of the population with it. Unlike the Tuscan nobility, Ferdinando and his brothers stayed in the city to try to ameliorate the general suffering.
Ferdinando was obsessed with new technology and had several hygrometers, barometers, thermometers and telescopes installed in the Palazzo Pitti. In 1654, influenced by Galileo, he is reported to have invented the sealed-glass thermometer by sealing the glass tip of a tube filled to a certain height with colored alcohol.
Ferdinando died in Florence at the Pitti Palace on 23 May 1670 at age 59 of apoplexy and dropsy. At that time the population of the grand duchy was 730,594; the streets were lined with grass and the buildings on the verge of collapse in Pisa.
Link to Wikipedia biography