In the surface of the moon,

in innumerable Fixed Stars,

in Nebulae, and above all

in FOUR PLANETS

swiftly revolving about Jupiter at differing distances and periods,

and known to no one before the Author recently perceived them

and decided that they should be named

THE MEDICEAN STARS

Venice 1610

The first four pages following this great proem of a title page were filled by a dedication to Cosimo Medici that was exceptionally florid even for Galileo. Jupiter had been in the ascendant at Cosimo’s birth, it pointed out; pouring out with all his splendor and grandeur into the most pure air, so that with its first breath Your tender little body and Your soul, already decorated by God with noble ornaments, could drink in this universal power…. Your incredible clemency and kindness … Most Serene Cosimo, Great Hero … when you have surpassed Your peers You will still contend with Yourself, which self and greatness You are daily surpassing, Most Merciful Prince … from Your Highness’s most loyal servant, Galileo Galilei.

The book was published in March of 1610. The first printing sold out within the month. Copies circulated throughout Europe. Indeed its fame was worldwide. Within five years word came that it was being discussed at the court of the Chinese emperor.

Despite this literary and scientific success, the Galilean household was still running at a loss, with Galileo’s time also massively overcommit-ted. He wrote to his friend Sagredo, I’m always at the service of this or that person. I have to eat up many hours of the day—often the best ones—in the service of others. I need a prince.

On May 7, 1610, he wrote a follow-up inquiry to Vinta. He did not beat around the bush, but made it an explicit letter of application, a real piece of rhetoric. He requested a salary of a thousand florins a year, and sufficient free time to bring to completion certain works he had in progress. Glancing up at the dusty workbooks on the shelf to make sure he forgot nothing, he made a list of what he hoped to publish if he were given the time:

Two books on the system and constitution of the universe, an overarching conception full of philosophy, astronomy, and geometry; three books on local motion, an entirely new science, as no one else ancient or modern has discovered the many amazing properties that I demonstrate to exist in natural and forced motions, which is why I may call this a new science discovered by me from its first principles; three books on mechanics, two pertaining to principles and foundations, one on its problems—and though others have written on this same material, what has been written to date is not one-quarter of what I will write, either in quantity or otherwise. I have also various little works on physical subjects, such as On Sound and Voice, On Vision and Colors, On the Tides, On the Composition of the Continuum, On the Motion of Animals, and still more. I will also write on military science, giving not only a model of what a soldier ought to be, but also mathematical treatises on fortification, the movement of troops, sieges, surveying, estimating distances and artillery power, and a fuller description of my military compass,

—which is in fact my greatest invention, he did not add—a single device that allows one to make all of the military calculations I have already mentioned plus also the division of lines, the solution of the Rule of Three, the equalization of money, the calculation of interest, proportional reduction of figures and solids, extraction of square and cube roots, identification of the mean proportionals, transformation of parallelepipeds into cubes, determination of proportional weights of metals and other substances, description of polygons and division of circumferences into equal parts, squaring of the circle or any other regular figures, taking the batter of scarps on walls—in short it was an omnicalculator, able to make any computation you could want, despite which hardly anyone has noticed its existence, and even fewer bought one, so stupid was the common run of humanity!

But that was not germane, even though the reaction to his compass still galled him and was one of the events driving this whole move back to Florence. It wasn’t a good subject to bring up, so he only moved to his conclusion:

Finally, as to the title and the scope of my duties, I wish in addition to the name of Mathematician that His Highness adjoin that of Philosopher. Whether I can and should have this title I shall be able to show Their Highnesses whenever it is their pleasure to give me a chance to deal with this in their presence with the most esteemed men of that profession,

—such as they are, being for the most part grossly overpaid Peripatetic idiots!

Reading over the final flourishes, and looking at the red leather of their best spyglass yet, embossed in gold with typical Florentine and Medici figures, it seemed to him that the opportunities being offered to any potential patron were too great to decline. What an application! Even the transport case into which everything was loaded for the Florentine courier was beautiful. Who could say no to such a thing?

And, in fact, on May 24, 1610, a reply from Vinta came to the house behind the church of Santa Giustina, the house on Via Vignali where they had all lived and worked together for eighteen years. Grand Duke Cosimo, Vinta wrote, accepts your services.

Galileo wrote to accept the acceptance on May 28. On June 5, Vinta wrote back, confirming that his title would be “Chief Mathematician of the University of Pisa and Philosopher to the Grand Duke.”

Galileo wrote back in turn, asking that his title be revised to “Mathematician and Philosopher to the Grand Duke.”

He also requested that he be absolved of any further obligation to his two brothers-in-law arising from defaults on dowry payments for his sisters. That would allow him to go home without the inconvenience of embarrassing lawsuits from those disgusting chiselers, or the possibility of arrest. He would go up to them in the streets and say to them, “I am mathematician and philosopher to the Grand Duke, go fuck yourselves.”

And all this was agreed to in his formal appointment of July 10, 1610. The new service to Cosimo was to begin in October. It was understood to be a lifetime appointment.

He had a Prince.

The move from Padua to Florence was complicated, and what had never been more than controlled chaos at Hostel Galileo fell into utter chaos. Among other more practical tasks, Galileo had to deal with a lot of hard feelings in Padua and Venice. Many of the Venetian pregadi were outraged to hear he was walking out on his acceptance of their recent offer, calling it gross ingratitude and worse. The procurator Antonio Priuli was particularly bitter. “I hope I never lay eyes on that ungrateful asshole again!” he was said to have shouted, and of course this was quickly reported to Galileo. And it wasn’t just Priuli; the anger was widespread. It was obvious Venice would never again offer him employment. He had cast his lot with Florence, and, people said grimly, it had better go well for him there, or else.

Galileo gritted his teeth and forged on with the chores of the move. This reaction was to be expected, it was just part of the price he had to pay to get patronage. It was a sign that the Venetians had valued him and yet taken advantage of him, and knew it and felt guilty about it, and as people would always rather feel angry than guilty, the transmutation of the one to the other had been easy. It had to be his fault.