Galileo, Reconsidered

The first biography of Galileo Galilei resurfaces and offers a new theory as to why the astronomer was put on trial

Galileo (Stefano Bianchetti/Corbis)

The classic image of Galileo Galilei has the 16th century Italian scientist dropping two balls of differing weights from the Leaning Tower of Pisa and observing them hitting the ground at the same time. Though that scenario was probably no more than one of Galileo's thought experiments—his known tests involved rolling balls down inclines—it does illustrate his towering reputation as a scientific revolutionary. Galileo helped pave the way for classic mechanics and made huge technological and observational leaps in astronomy. Most famously, he championed the Copernican model of the universe, which put the sun at its center and the earth in orbit. The Catholic Church banned Galileo's 1632 book Dialogue Concerning the Two Chief World Systems, forced Galileo to recant his heliocentric views and condemned him to house arrest. He died in his Florence home in 1642.

Historians of science have long debated the exact nature of and motivations for Galileo's trial. War, politics and strange bedfellows obscure science's premier martyrdom story. Many of the documents historians use to try and untangle the mystery are mired in their own prejudices or were written long after the fact, or both.

Now the very first written biography of Galileo has been rediscovered. It offers a rare glimpse into what people thought about the trial only 20 years after Galileo's death and even suggests a tantalizing new explanation for why he was put on trial in the first place.

Following Galileo's death, his apprentice, Vincenzo Viviani, collected Galileo's books and correspondences and announced his intention to write the definitive history of Galileo. Due to Viviani's privileged position, most other would-be biographers deferred to him. But by the 1660s, Viviani still had not written his promised masterpiece.

Enter Thomas Salusbury, an English historian who in 1664 published his Galilean oeuvre, Mathematical Collections and Translations. Composed of two volumes, the collection contained translations of Galileo's various discourses, letters, and the first book-length depiction of Galileo's life.

Then in 1666, the Great Fire of London swept through the city. The book trade in particular was badly hit; many publishing houses became piles of ashes overnight. In the inferno, all but a single copy of Salusbury's biography were lost. Salusbury died at about the same time—possibly in the fire, or maybe from the plague. By late 1666, Mrs. Susan Salusbury was a known widow.

But the book lived on. It passed through various hands before, in 1749, it wound up in the private library of George Parker, Second Earl of Macclesfield, a respected amateur astronomer. The 1830s marked the last time that the book was directly quoted. After that, the trail goes cold. Historians searched the Macclesfield library again and again, only to wind up empty-handed, and most were resigned to the fact that the book was lost.

In 2003, Richard Parker, the Ninth Earl of Macclesfield, was evicted from the family castle following a bitter property dispute with the castle's management company, whose shareholders included his own relatives. The 30-year family feud precipitating the eviction was based on, as the presiding judge put it, simple "palpable dislike." Upon his ousting, the Earl auctioned off the contents of the castle's three libraries.

Nick Wilding, an associate professor of history at Georgia State University, heard the libraries were up for auction and immediately called the Sotheby's representative in charge of the affair. Wilding asked him, doubtfully, if in the collection he had chanced across a particular title: Galilaeus Galilaeus His Life: In Five Books, by Thomas Salusbury. "To my surprise, he said, 'Why, yes, actually. I've got it right here,'" Wilding recalls. He hopped on the next plane to London.

Perusing the tattered tome at Sotheby's auction house, Wilding became the first person to study Salusbury's mysterious biography of Galileo in almost 200 years. Inside the timeworn document itself, Wilding discovered clues that allowed him to piece together its elusive, seemingly cursed history.


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