Birth and family. Galileo Galilei was born in Pisa, Italy, on 16th February 1564. From an Anglo-centric point-of-view, that was the sixth year of the reign of Queen Elizabeth I. William Shakespeare was born a couple of months later, on or about 23rd April.

According to Vincenzio Viviani (1622-1703), Galileo’s last pupil and early biographer , ‘his parents were then living there [in Pisa] for family business [per domestici affari]. His father was Vincenzio di Michelangelo Galilei, a gentleman very adept in mathematics and, especially, in the theory of music [musica speculativa] . . . . He had more children of Signora Giulia Ammannati his wife, but Galileo was the oldest of his sons.’

At that time Pisa was part of the Duchy of Tuscany, and ruled from the capital Florence by the able, ruthless Duke Cosimo de’ Medici.

Education. The Galilei were an old established Florentine family, albeit now seriously impoverished. Nonetheless Galileo received an extensive classical and scholastic education. From 1581 to 1585 he studied at – well, attended – the university of Pisa, with a view to becoming a doctor, but left without taking a degree. After several intriguing ‘gap’ years – in which Galileo’s Revenge is set – Galileo managed to secure a job as professor of mathematics, first in 1589 at Pisa and then in 1592 at the more prestigious university of Padua. Mathematics was generally regarded as a fairly humble discipline, certainly as compared to philosophy or medicine.

Stardom. It wasn’t until 1609, aged 45, that Galileo got his big break. Reverse-engineering (or maybe just stealing) the secret of the newly-invented telescope, he turned it upon the night sky. Within a couple of months he rushed into print with his Starry Messenger (Sidereus Nuncius), a slim volume describing his observations of the mountains on the Moon, of the Milky Way and, above all, of the previously unknown moons of Jupiter. This was his ticket to lavish patronage by the most powerful courts at Florence and Rome. He was soon the most famous scientist in Europe.

Heresy. [image: Dialogues titlepage] Galileo spent the next two decades engaged in often bad-tempered polemics defending and extending his astronomical discoveries.

Eventually, in 1632, he published his Dialogues upon the Two Chief World Systems (Dialoghi sopra i due massimi sistemi del mondo), championing the still-contentious Copernican theory that made the Earth revolve around the Sun (rather than vice cersa). Unfortunately he had misread the mood of the Vatican, and the Roman Inquisition judged him to be ‘vehemently suspected of heresy’. He was forced to repudiate his Copernican beliefs and condemned to house arrest outside Florence for the rest of his life.

Free fall. There was a silver lining. In his humiliated isolation Galileo finally got around to publishing the Discoures on Two New Sciences (Discorsi) explaining his much earlier findings in mechanics, such as the uniform acceleration of falling bodies, the parabolic path of projectiles, and the isochronicity of the pendulum – which lead him to design the first pendulum clock. He died in January of 1642. Newton was born the following Christmas.

Potted nutshell. Galileo Galilei, Italian astronomer and scientist. Born Pisa, 1564. Discovered moons of Jupiter with telescope in 1610. Condemned for heresy by Inquisition in 1633. Died Florence, 1642.