Biographies & Memoirs


This grand book the universe

The recently deceased relative Suor Maria Celeste mourned in her first extant letter was Virginia Galilei Landucci, the aunt she’d been named after. At the Convent of San Matteo, she shared her grief with her natural sister, Suor Arcangela (originally the namesake of Galileo’s other sister, Livia), and also with her cousin Suor Chiara—the departed Virginia’s own daughter Virginia.

A repetition of recollected identities echoed through the Galilei family like the sound of chanting, with its most melodic expression in the poetic rhythm of the great scientist’s full name. By accepted practice among established Tuscan families in the mid-sixteenth century, when Galileo was born, the eldest son might well receive a Christian name derived from his parents’ surname. Accordingly, Vincenzio Galilei and his new wife, Giulia Ammannati Galilei, attracted no special attention when they gave the name Galileo to their first child, born at Pisa on the fifteenth day of February in the year of our Lord 1564. (The year was actually recorded as 1563 in the chronicles of that period, however, when New Year’s Day fell on March 25—the feast of the Annunciation.)

The family name Galilei, ironically, had itself been created from the first name of one of its foremost favorite sons. This was the renowned doctor Galileo Buonaiuti, who taught and practiced medicine during the early 1400s in Florence, where he also served the government loyally. His descendants redubbed themselves the Galilei family in his honor and wrote “Galileo Galilei” on his tombstone, but retained the coat of arms that had belonged to the ancestral Buonaiutis since the thirteenth century—a red stepladder on a gold shield, forming a pictograph of the word buonaiuti, which literally means “good help.” The meaning of the name Galileo, or Galilei, harks back to the land of Galilee, although, as Galileo explained on this score, he was not at all a Jew.






Galileo Galilei took a few tentative steps along his famous forebear’s path, studying medicine for two years at the University of Pisa, before he gave himself over to the pursuit of mathematics and physics, his true passion. “Philosophy is written in this grand book the universe, which stands continually open to our gaze,” Galileo believed. “But the book cannot be understood unless one first learns to comprehend the language and to read the alphabet in which it is composed. It is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures, without which it is humanly impossible to understand a single word of it; without these, one wanders about in a dark labyrinth.”

Galileo’s father had opposed the idea of his becoming a mathematician and tried, arguing from long personal experience with mathematics and patrician poverty, to dissuade his son from choosing such a poorly paid career.

Vincenzio made a minimal living giving music lessons in the rented Pisan house where Galileo was born and partly raised. He also dabbled in the business dealings of his wife’s family, the Ammannati cloth merchants, to supplement his small teaching income, but he was at heart a composer and musical theorist in the days when musical theory was considered a special branch of mathematics. Vincenzio taught Galileo to sing, and to play the organ and other instruments, including the recently remodeled lute, which became their favorite. In the course of this instruction he introduced the boy to the Pythagorean rule of musical ratios, which required strict obedience in tuning and composition to numerical properties of notes in a scale. But Vincenzio subjected these prevailing rules to his own studies on the physics of sound. Music, after all, arose from vibrations in the air, not abstract concepts regarding whole numbers. Using this philosophy, Vincenzio established an ideal tuning formula for the lute by fractionally shortening the intervals between successive frets.

After Vincenzio moved to Florence with his wife in 1572, temporarily leaving Galileo behind in the care of relatives, he joined other virtuoso performers, scholars, and poets bent on reviving classic Greek tragedy with music.* Vincenzio later wrote a book defending the new trend in tuning that favored the sweetness of the instrument’s sound over the ancient adherence to strict numerical relationships between notes. This book openly challenged Vincenzio’s own former music teacher, who prevented its publication in Venice in 1578. Vincenzio persevered, however, until he saw the work printed in Florence three years later. None of these lessons in determination or challenge to authority was lost on the young Galileo.

“It appears to me,” Vincenzio stated in his Dialogue of Ancient and Modern Music, “that they who in proof of any assertion rely simply on the weight of authority, without adducing any argument in support of it, act very absurdly. I, on the contrary, wish to be allowed freely to question and freely to answer you without any sort of adulation, as well becomes those who are in search of truth.”

When Galileo was ten, he journeyed across Tuscany to join his parents and his infant sister, Virginia, in Florence. He attended grammar school near his new home until his thirteenth year, then moved into the Benedictine monastery at Vallombrosa to take instruction in Greek, Latin, and logic. Once there, he joined the order as a novice, hoping to become a monk himself, but his father wouldn’t let him. Vincenzio withdrew Galileo and took him home, blaming an inflammation in the youth’s eyes that required medical attention. Money more likely decided the issue, for Vincenzio could ill afford the down payment and regular upkeep required to support his son in a religious vocation that generated no income. A girl was different. Vincenzio would have to pay dowries for his daughters, either to the Church or to a husband, and he could expect no return on either investment. Thus Vincenzio needed Galileo to grow up gainfully employed, preferably as a doctor, so he could help support his younger sisters, now four in number, and two brothers.

Vincenzio planned to send Galileo back to Pisa, to the College of the Sapienza, as one of forty Tuscan boys awarded free tuition and board, but couldn’t obtain the necessary scholarship. A good friend of Vincenzio’s in Pisa offered to take Galileo into his own home, to reduce the cost of the boy’s education. Vincenzio, however, hearing that this friend was romancing one of Galileo’s Ammannati cousins, held off for three years until the love affair ended in marriage and made the house a respectable residence for his son.

In September of 1581, Galileo matriculated at the University of Pisa, where medicine and mathematics both fit into the Faculty of Arts. Although he applied himself to the medical curriculum to please his father, he much preferred mathematics from the moment he encountered the geometry of Euclid in 1583. After four years of formal study, Galileo left Pisa in 1585, at age twenty-one, without completing the course requirements for a degree.

Galileo returned to his father’s house in Florence. There he began behaving like a professional mathematician—writing proofs and papers in geometry, going out to give occasional public lectures, including two to the Florentine Academy on the conic configuration of Dante’s Inferno, and tutoring private students. Between 1588 and 1589, when Vincenzio filled a room with weighted strings of varying lengths, diameters, and tensions to test certain harmonic ideas, Galileo joined him as his assistant. It seems safe to say that Galileo, who gets credit for being the father of experimental physics, may have learned the rudiments and value of experimentation from his own father’s efforts.

Having impressed several established mathematicians with his talent, Galileo procured a teaching post at the University of Pisa in 1589, and returned once more to the city of his birth at the mouth of the River Arno. The flooding of the river in fact delayed Galileo’s arrival on campus, so that he missed his first six lectures and found himself fined for these absences. By the end of the year, the university authorities were docking his pay for a different sort of infraction: his refusal to wear the regulation academic regalia at all times.

Galileo deemed official doctoral dress a pretentious nuisance, and he derided the toga in a three-hundred-line verse spoof that enjoyed wide readership in that college town. Any kind of clothing got in the way of men’s and women’s frank appraisals of each other’s attributes, he argued in ribald rhyme, while professional uniforms hid the true merits of character under a cloak of social standing. Worse, the dignity of the professor’s gown barred him from the brothel, denying him the evil pleasures of whoring while resigning him to the equally sinful solace of his own hands. The gown even impeded walking, to say nothing of working.

A long black robe would surely have hindered Galileo’s progress up the Leaning Tower’s eight-story spiral staircase, laden, as legend has it, with cannonballs to demonstrate a scientific principle. In that infamous episode, the weight of iron on the twenty-five-year-old professor’s shoulders was as nothing compared to the burden of Aristotelian thought on his students’ perceptions of reality. Not only Galileo’s classes at Pisa, but university communities all over Europe, honored the dictum of Aristotelian physics that objects of different weights fall at different speeds. A cannonball of ten pounds, for example, would be expected to fall ten times faster than a musket ball of only one pound, so that if both were released together from some summit, the cannonball would land before the musket ball had gotten more than one-tenth of the way to the ground. This made perfect sense to most philosophical minds, though the thought struck Galileo as preposterous. “Try, if you can,” Galileo exhorted one of his many opponents, “to picture in your mind the large ball striking the ground while the small one is less than a yard from the top of the tower.”

“Imagine them joining together while falling,” he appealed to another debater. “Why should they double their speed as Aristotle claimed?" If the incongruity of these midair scenarios didn’t deflate Aristotle’s ideas, it was a simple enough matter to test his assertions with real props in a public setting.

Galileo never recorded the date or details of the actual demonstration himself but recounted the story in his old age to a young disciple, who included it in a posthumous biographical sketch. However dramatically Galileo may have executed the event, he did not succeed in swaying popular opinion down at the base of the Leaning Tower. The larger ball, being less susceptible to the effects of what Galileo recognized as air resistance, fell faster, to the great relief of the Pisan philosophy department. The fact that it fell only fractionally faster gave Galileo scant advantage.

“Aristotle says that a hundred-pound ball falling from a height of a hundred braccia [arm lengths] hits the ground before a one-pound ball has fallen one braccio. I say they arrive at the same time,” Galileo resummarized the dispute in its aftermath. “You find, on making the test, that the larger ball beats the smaller one by two inches. Now, behind those two inches you want to hide Aristotle’s ninety-nine braccia and, speaking only of my tiny error, remain silent about his enormous mistake.”

Indeed this was the case. Many philosophers of the sixteenth century, unaccustomed to experimental proof, much preferred the wisdom of Aristotle to the antics of Galileo, which made him an unpopular figure at Pisa.

When Vincenzio died in 1591 at the age of seventy, Galileo assumed financial responsibility for the whole family on a math professor’s meager salary of sixty scudi annually. (Professors in the more venerated field of philosophy made six to eight times as much, while a father confessor could earn close to two hundred scudi per year, a well-trained physician about three hundred, and the commanders of the Tuscan armed forces between one thousand and twenty-five hundred.) Galileo paid out dowry installments to his newly married sister Virginia’s fractious husband, Benedetto Landucci, supported his mother and sixteen-year-old brother, Michelangelo, and maintained his sister Livia at the Convent of San Giuliano until he could arrange for her to be wed. By this time, his three other siblings had all died of childhood diseases.

Galileo lent his help ungrudgingly, even enthusiastically. “The present I am going to make Virginia consists of a set of silken bed-hangings,” he had written home from Pisa just before her wedding. “I bought the silk at Lucca, and had it woven, so that, though the fabric is of a wide width, it will cost me only about three carlini [about one-hundredth of a scudo] the yard. It is a striped material, and I think you will be much pleased with it. I have ordered silk fringes to match, and could very easily get the bedstead made, too. But do not say a word to anyone, that it may come to her quite unexpectedly. I will bring it when I come home for the Carnival holidays, and, as I said before, if you like I will bring her worked velvet and damask, stuff enough to make four or five handsome dresses.”

In 1592, the year after he buried his father in the Florentine church called Santa Croce, Galileo left Pisa for the chair of mathematics at the University of Padua. If he had to forsake his native Tuscany for the Serene Republic of Venice, at least he enjoyed a more distinguished position there and increased his income to 180 Venetian florins per year.


The University of Padua, where Galileo taught for eighteen years

From the perspective of old age, Galileo would describe his time in Padua as the happiest period of his life. He made important friends with some of the republic’s great cultural and intellectual leaders, who invited him to their homes as well as to consult on shipbuilding at the Venetian Arsenale. The Venetian senate granted him a patent on an irrigation device he invented. Galileo’s influential supporters and quick-spreading reputation as an electrifying lecturer earned him raises that pushed his university salary to 300 and then to 480 florins annually. At Padua he also pursued the seminal studies of the properties of motion that he had begun in Pisa, for wise men regarded motion as the basis of all natural philosophy.

Fatefully during his Paduan idyll, while visiting friends outside the city, Galileo and two gentleman companions escaped the midday heat one afternoon by taking a siesta in an underground room. Natural air-conditioning cooled this chamber by means of a conduit that delivered wind from a waterfall inside a nearby mountain cave. Such ingenious systems ventilated numerous sixteenth-century villas in the Italian countryside but may have admitted some noxious vapors along with the welcome zephyrs, as apparently occurred in Galileo’s case. When the men awoke from their two-hour nap, they complained of various symptoms including cramps and chills, intense headache, hearing loss, and muscle lethargy. Within days, the strange malaise proved fatal for one of its victims; the second man lived longer but also died of the same exposure. Galileo alone recovered. For the rest of his life, however, bouts of pain, later described by his son as arthritic or rheumatic seizures, would strike him down and confine him to his bed for weeks on end.

Under happier circumstances—although no one knows precisely when or how—Galileo in Padua met Marina Gamba, the woman who shared his private hours for twelve years and bore him three children.

Marina did not share his house, however. Galileo dwelled on Padua’s Borgo dei Vignali (renamed, in recent times, Via Galileo Galilei). Like most professors, he rented out rooms to private students, many of them young noblemen from abroad, who paid to board under his roof for the duration of their private lessons with him. Marina lived in Venice, where Galileo traveled by ferry on the weekends to enjoy himself. When she became pregnant, he moved her to Padua, to a small house on the Ponte Corvo, only a five-minute walk away from his own (if one could have counted minutes in those days). Even after the ties between Marina and Galileo were strengthened by the growth of their family, their separate living arrangement remained the same.

Suor Maria Celeste Galilei, nee “Virginia, daughter of Marina from Venice,” was “born of fornication,” that is to say, out of wedlock, according to the parish registry of San Lorenzo in the city of Padua, on the thirteenth of August 1600, and baptized on the twenty-first. Marina was twenty-two on this occasion, and Galileo (though no mention divulges his identity), thirty-six. Such age discrepancies occurred commonly among couples at that time. Galileo’s own father had reached forty-two years before taking the twenty-four-year-old Giulia as his bride.


Engraving of Galileo at age thirty-eight, by Joseph Calendi

The following year, 1601, again in August, a registry entry on the twenty-seventh marked the baptism of “Livia Antonia, daughter of Marina Gamba and of—” followed by a blank space.

After five more years, on August 22, 1606, a third child was baptized, “Vincenzio Andrea, son of Madonna Marina, daughter of Andrea Gamba, and an unknown father.” Technically an “unknown father” for being unmarried to the mother, Galileo nevertheless asserted his paternity by giving the baby both grandfathers’ names.

Galileo recognized his illegitimate children as the heirs of his lineage, and their mother as his mate, although he ever avoided marrying Marina. Scholars by tradition tended to remain single, and the notations in the parish registry hint at circumstances that would have strengthened Galileo’s resolve. After all, she was “Marina from Venice"—not from Pisa or Florence, or Prato or Pistoia, or any other town within the bounds of Tuscany, where Galileo determined to return someday. And her heritage, “daughter of Andrea Gamba,” did not put her on a par with the poor but patrician Galilei family, whose ancestors had signed their names in the record books of a great city government.

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