now would surely welcome news of Galileo’s recent work. Grand Duke Cosimo condoned the trip. He thought it might heighten his own stature in Rome, where his brother Carlo currently filled the traditional position of resident Medici cardinal.
Unfortunately, Galileo’s sickly reaction to the air of Florence prevented him from setting out until 23 March 1611. He spent six days on the road in the grand duke’s litter, and at night he set up his telescope in every stop along the way – San Casciano, Siena, San Quirico, Acquapendente, Viterbo, Alonterosi – to continue tracking the revolutions of Jupiter’s moons.
Upon Galileo’s arrival at the week’s end, the warmth of his Roman welcome surprised him. ‘I have been received and fêted by many illustrious cardinals, prelates and princes of this city,’ he reported, ‘who wanted to see the things I have observed and were much pleased, as I was too on my part in viewing the marvels of their statuary, paintings, frescoed rooms, palaces, gardens, etc.’
Galileo garnered the powerful endorsement of the Collegio Romano, the central institution of the Jesuit educational net-work, where Father Clavius, now well into his seventies, was chief mathematician. He and his revered colleagues, regarded by the Church as the top astronomical authorities, had obtained telescopes of their own, and now as a group corroborated all of Galileo’s observations. Bound as these Jesuits were to Aristotelian belief in an unchanging cosmos, they did not deny the evidence of their senses. They even honoured Galileo with a rare invitation to visit.
‘On Friday evening of the past week in the Collegio Romano,’ a social bulletin reported in early April, ‘in the presence of cardinals and of the Marquis of Monticelli, its promoter, a Latin oration was recited, with other compositions in praise of Signor Galileo Galilei, mathematician to the grand duke, magnifying and exalting to the heavens his new observation of new planets that were unknown to the ancient philosophers.’
This marquis of Monticelli who attended Galileo’s fête was an affable, idealistic young Roman named Federico Cesi. His handful of noble titles also pronounced him duke of Acquasparta and prince of San Polo and Sant’ Angelo. In addition to these honours he bore by birth, he had distinguished himself in 1603, at the age of eighteen, by founding the world’s first scientific society, the Lyncean Academy. Cesi pooled his wealth, foresight and curiosity to establish a forum free from university control or prejudice. He made the academy international from the outset – one of its four charter members being Dutch – and multidisciplinary by design: ‘The Lyncean Academy desires as its members philosophers who are eager for real knowledge and will give themselves to the study of nature, especially mathematics; at the same time it will not neglect the ornaments of elegant literature and philology, which, like graceful garments, adorn the whole body of science.’ The choice of the sharp-eyed lynx as totem emphasised the importance Cesi placed on faithful observation of Nature. At official ceremonies, Cesi sometimes wore a lynx pendant on a gold neck chain.
Cesi entreated Galileo, who embodied the Lynceans’ organising principles, to join the academy during his stay in Rome. He held a banquet in Galileo’s honour on 14 April on the city’s highest hill, where one of the other dinner guests, Greek mathematician Giovanni Demisiani, proposed the name ‘telescope’ for the spyglass Galileo had brought along to show the party the moons of Jupiter. The men lingered long into the night enjoying the novel views. To dispel any possible doubt about his instrument’s veracity, Galileo also aimed the telescope point-blank at the exterior wall of the Lateran Church, where a chiselled inscription attributed to Pope Sixtus V could be easily read by all, though it stood over a mile away.
Galileo’s formal election to the Lyncean Academy the next week privileged him to add the title ‘Lyncean’ after his signature on any literary work or private correspondence, which practice he took up immediately. Furthermore the academy, Cesi promised, would become Galileo’s publisher.
Before leaving Rome triumphant at the end of May, Galileo gained a favourable audience with the reigning pope, Paul V, who ordinarily took no great interest in science or scientists. Galileo also made the acquaintance of Maffeo Cardinal Barberini, the man destined to become the future Pope Urban VIII. Cardinal Barberini, a fellow Tuscan roughly the same age as Galileo and, like him, an alumnus of the University of Pisa, admired the court philosopher’s scientific work and shared his interest in poetry.
Chance threw Galileo and Barberini together again the following autumn, in Florence, when the visiting cardinal was the grand duke’s dinner guest, and Galileo the after-dinner entertainment. On that night, 2 October 1611, Galileo staged a debate with a philosophy professor from Pisa, arguing on the subject of floating bodies for the edification of all present. Galileo’s explanation of what made ice and other objects float in water differed sharply from the Aristotelian logic being taught in the universities, and his adroit verbal decimation of any opponent made for spectator sport at the Tuscan court. ‘Before answering the adversaries’ arguments,’ a contemporary observer reported of Galileo’s debating style, ‘he amplified and reinforced them with apparently very powerful evidence which then made his adversaries look more ridiculous when he eventually destroyed their positions.’
The prevailing wisdom about bodies in water held that ice was heavier than water, but that broad, flat-bottomed pieces of ice floated anyway because of their shape, which failed to pierce the fluid surface. Galileo knew ice to be less dense than water, and therefore lighter, so that it always floated, regardless of its shape. He could show this by submerging a piece of ice and then releasing it under water to let it pop back up to the surface. Now, if shape were all that kept ice from sinking, then shape should also prohibit its upward motion through water – and all the more so if ice truly outweighed water.
Invited to join the discussion on floating bodies, Cardinal Barberini enthusiastically took Galileo’s side. Later, he told Galileo in a letter: ‘I pray the Lord God to preserve you, because men of great value like you deserve to live a long time to the benefit of the public.’
Cardinal Barberini had come to Florence to visit two of his nieces – both nuns, who lived at a local convent. This coincidence may have suggested a course to Galileo concerning his own two daughters, though the thought of placing them in a convent could have occurred to him naturally enough. Not only had his two sisters been schooled and sheltered in convents, but such institutions proliferated all around him. In Galileo’s time, in addition to nearly thirty thousand males of all ages and more than thirty-six thousand females living in the city of Florence, a separately tallied population of ‘religious’ – one thousand men and four thousand women – dwelled in twenty-seven local monasteries and fifty-three convents. The pealing of bells from atop these cloistered residences reverberated through the air, day and night, as constant a note in the din of life as birdsong or conversation. Fully 50 per cent of the daughters of Florentine patrician families spent at least part of their lives within convent walls.
Galileo’s sisters had eventually left the convent for holy matrimony, but he foresaw no such future for his daughters because of the conditions of their birth. At their present ages, eleven and ten, they were too young to take religious vows, yet they might well enter a convent before the canonical age of sixteen in any case, and bide the intervening years in a safer environment than he could provide for them, considering the plights of the women in his family: Madonna Giulia, always argumentative, had grown more difficult as she grew older, while his sisters were both burdened with their own young children and frequent pregnancies.
Galileo’s poor health perhaps rushed his judgment on the matter, since he again took seriously ill within days of the court dispute over floating bodies and did not recover for several months. His illness forced him to flee the city for his private sanatorium at the Villa delle Selve, the country home of a generous good friend. From his bed in the hills, at the grand duke’s behest, Galileo began putting his thoughts on floating bodies into a book-length treatment, to be called Discourse on Bodies That Stay Atop Water or Move Within It.
While at work on this project, he
