Once moved in, Galileo launched into a busy schedule of visits to dignitaries strategic to his purpose. One of the most important of these came when he called on the Jesuit Christopher Clavius and his younger colleagues at the College of Rome.
Clavius greeted him with the same words he had used twenty-four years before, when Galileo had been an unknown young mathematician and Clavius in his prime, known through Europe as “the Euclid of the sixteenth century.”
“Welcome to Rome, young signor. All praise to God and Archimedes!”
He was not much changed in appearance, despite all the years: a slight man with a puckered mouth and a kindly eye. He led Galileo into the Jesuit college’s workshop, where together they inspected the spyglasses the monk mechanicals had constructed. The glasses looked like Galileo’s, and were equivalent in power, although more marred by irregularities, as Galileo told the monks freely.
Christopher Grienberger and Odo Maelcote then joined them, and Clavius introduced them as the ones who had made the bulk of the observations; Clavius lamented his aged eyesight. “But I have seen your so-called Medicean Stars several times,” he added, “and they are obviously orbiting Jupiter, just as you say.”
Galileo bowed deeply. There were people out there claiming the moons were just flaws in Galileo’s glass. He had angrily offered ten thousand crowns to anyone who could make a glass that would show flaws around Jupiter but not around the other planets, and of course there were no takers, but still—not everyone believed. So this mattered. Seeing was believing, and Clavius had seen. As Galileo straightened up, he said, “God bless you, Father. I was quite sure that you would see them, they are so prominent, and you such an experienced astronomer. And I can tell you that on my journey to Rome I have made good progress in determining the period of orbit of all four of these new moons.”
Grienberger and Maelcote raised their eyebrows and exchanged glances, but Clavius only smiled. “I think here we are in rare agreement with Johannes Kepler, that establishing their periods of rotation will be very difficult.”
“But …” Galileo hesitated, then realized he had made a mistake, and dropped the matter with a wave of the hand. There was no point in making announcements in advance of results; indeed, since he was intent on being the first to make every discovery having to do with the new stars, he should not be inciting competitors to further effort. It was already startling enough to see that they had managed to manufacture spyglasses almost as strong as his.
So he let the talk turn to the phases of Venus. They also had seen these, and while he did not press the point that this was strong evidence in support of the Copernican view, he could see in their faces that the implications were already clear to them. And they did not deny the appearances. They believed in the glass. This was a most excellent sign, and as he considered the happy implications of their public acknowledgment that their observations agreed with his, Galileo recovered from his uneasiness at the power of their devices. These were the pope’s official astronomers, supporting his findings! So he spent the rest of the afternoon reminiscing with Clavius and laughing at his jokes.
The next important meeting for Galileo, though he did not know it, came on the Saturday before Easter, when he paid his respects to Cardinal Maffeo Barberini. They met in one of the outer offices of St. Peter’s, near the Vatican’s river gate. Galileo examined the interior gardens of the place with a close eye; he had never been inside the sacred fortress before, and it was interesting to observe the horticulture deployed inside. Purity had been emphasized over liveliness, he was not surprised to note. Paths were graveled, borders were lines of clean cobbles, long narrow lawns were trimmed as if by barbers. Massed roses and camelias were all either white or red. It was a little too much.
Barberini proved to be a man of the world—affable, quick, well-dressed in a cardinal’s everyday finery; lithe and handsome, goateed, smooth-skinned, fulsome. His power made him as graceful as a dancer, as confident in his body as a minx or otter. Galileo handed him the introductory letters from Michelangelo’s nephew and from Antonio de Medici, and Barberini put them aside after a glance and took Galileo by the hand and led him out into his office’s courtyard, dispensing with all ceremony. “Let’s take our ease and talk.”
Galileo was his usual lively self, a happy man with a genius for mathematics. In these interviews with nobles, he was quick and funny, always chuckling in his baritone rumble, ready to please. He did not know much about this cardinal, but the Barberini were a powerful family, and what he had heard was that Maffeo was a virtuoso, with a great interest in intellectual and artistic matters. He hosted many evenings in which poetry and song and philosophical debates were featured entertainments, and he wrote poetry himself that he was said to be vain about. Galileo seemed to be assuming that this was therefore a prelate in the style of Sarpi, broad-minded and liberal. In any case he was perfectly at ease, and showed Barberini his occhialino inside and out.
“I wish I had been able to bring enough of them with me to leave one with you as a gift, Your Eminence, but I was only allowed a small traveling trunk for baggage.”
Barberini nodded at this awkwardness. “I understand,” he murmured as he looked through it. “Seeing through yours is enough, for now, and more than enough. Although I do want one, it is true. It’s simply amazing how much you can see.” He pulled back to look at Galileo. “It’s odd—you wouldn’t think that more could be held there for the eye, in distant things, than we already see.”
“No, it’s true. We must admit that our senses don’t convey everything to us, not even in the sensible world.”
“Certainly not.”
They looked through it at the distant hills east of Rome, and the cardinal marveled and clapped him on the shoulder in the manner of any other man.
“You have given us new worlds,” he said.
“The seeing of them, anyway,” Galileo corrected him, to seem properly humble.
“And how do the Peripatetics take it? And the Jesuits?”
Galileo tipped his head side to side. “They are none too pleased, Your Grace.”
Barberini laughed. He had been trained by the Jesuits, but he did not like them, Galileo saw, and so continued. “There are some of them who refuse to look through the glass at all. One of them recently died, and as I said at the time, since he would not look at the stars through my glass, he could now inspect them from up close, on his way past them to Heaven!”
Barberini laughed uproariously. “And Clavius, what does he say?”
“He admits the moons orbiting Jupiter are really there.”
“The Medici moons, you have called them?”
“Yes,” Galileo admitted, realizing for the first time how this could be another awkwardness. “I expect to make many more discoveries in the heavens, and hope to honor those who have helped me accordingly.”
The little smile that twitched over the cardinal’s face was not entirely friendly. “And you think these Jovian moons show that the Earth goes around the sun in an analogous manner, as Copernicus claimed?”
“Well, it shows at least that moons go around planets, as our moon goes around the Earth. Better proof of the Copernican view, Your Grace, is how you can see the phases of Venus through the glass.” Galileo explained how in the Copernican understanding the phases of Venus had combined with its varying distance from Earth to make it seem to the naked eye as if it had always the same brightness, which had argued against the idea it had phases, when one had no glass to see them; and how its position, always low in the sky in the mornings and evenings, added to the actual discovery of the phases through the glass to support the idea that Venus was orbiting the sun inside the Earth’s own orbiting of the sun. The ideas were complicated to describe in words, and Galileo felt at ease enough to stand and take three citrons from a bowl, then place them and move them about on the table to illustrate the concepts, to Barberini’s evident delight.