Document Highlights

February 2002

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Engraving by G. Villamena of "Galileo Galilei, Member of the Academy of the Lincei, Philosopher and Mathematician of the Most Serene Grand Duke of Tuscany."

DOCUMENT CITATION:
Archivio di Stato di Firenze, Mediceo del Principato 300, fol. 136r-v.
(Entry 13860 in the "Documentary Sources" database.)

TRANSLATION:
We hereby authorize you to debit to our expenses 235 scudi, 3 lire and 10 denari (at 7 1/2 lire per scudo) equalling the 297 1/12 ducats disbursed by [Filippo and Piero] Mannelli in Venice, at an exchange rate of 79 1/6 % to be paid to Agostino Parenti and Company silk merchants for the 100 Spanish gold doubloons that they paid to the Excellent Gentleman Giulio Galilei, lecturer at the University of Padua, for services rendered to us. This money will be credited to you when you balance your books.

TRANSCRIPTION:
[...] In virtù di questo nostro mandato mettete a uscita a spese nostre Generali [abbreviazione: scudi] dugento trentacinque [abbreviazione: soldi] iii x d'oro, [in margine: 235.3.10] di [abbreviazione: lire] 7 1/2 per scudo, per valuta di ducati 297 0/12 correnti, stativi rimessi tutti di Venetia da Mannelli [Filippo e Piero] a 79 0/6 per cento in Agostino Parenti et compagni setaioli per valersi di cento doble d'oro di spagna di peso che hanno pagato per nostra commessione all'Ecc.te S.r Giulio [sic] Galilei lettore dello studio di Padova per nostro servizio, et vi saranno fatti buoni al saldo de vostri conti [...]

HISTORICAL CONTEXT:
Giulio Galilei, Lecturer at the University of Padua? Considering the extraordinary subsequent fame of Galileo Galilei, it is unsettling to see even his name getting lost in the bureaucratic shuffle. "Giulio", however, was a far more common first name than "Galileo" and in May of 1608, the forty-four year-old astronomer was just on the verge of becoming an international phenomenon.

Two years later in 1610, Galileo Galilei (1564-1638) published his epoch-making Sidereus Nuncius ("The Starry Messenger"), announcing his telescopic discovery of the moons of Jupiter (flatteringly renamed "The Medicean Planets") and the mountains of the solar moon. This resulted in his appointment as Chief Mathematician and Philosopher to Grand Duke Cosimo II de’ Medici and marked the beginning of his turbulent public career.

In the years leading up to this burst of recognition, Galileo had worked strenuously to achieve a position at the Medici Court. The man who emerges from the documents was an energetic self-promoter and very much a self-made man. This offers a useful balance to the popular characterization of Galileo Galilei as an ivory tower philosopher and a starry-eyed defender of abstract truth.

In Padua in 1597, Galileo began to manufacture a new kind of ‘military compass’, which was in fact a proportional compass or sector that performed a range of complex mathematical calculations, especially relevant to problems of ballistics. To supplement his university salary, he gave private lessons and marketed his compass, fiercely guarding his intellectual property rights to this invention. In 1605, for example, he substituted his manuscript user’s manual with a fuller printed version (Le operazioni del compasso geometrico e militare, dedicated to Prince Cosimo de’ Medici) when he discovered a Latin treatise plagiarizing his ideas. He eventually succeeded in having all unsold copies of the rival work confiscated and the author expelled from the University of Padua.

For many years, until his startling astronomical revelations, the military compass was Galileo’s main bargaining chip with the Medici. Then in 1605, he began spending his summer breaks in Florence, giving mathematical instruction to the young Prince Cosimo (who became Grand Duke Cosimo II in 1609.) Galileo had no regular contract for this tuition and had to reapply for the job each year. The present document most likely authorizes payment for one of these summer trips.

Now that we have entered the age of the credit card, the automatic teller machine and most recently the Euro, it is difficult to imagine how difficult it was to move money even between nearby Italian states a few centuries ago. As expressed in Ferdinando I de’ Medici’s order, Galileo’s honorarium left Florence as scudi, was turned into Venetian ducati and finally reached him as Spanish doble d’oro (gold doubloons)—at least on paper.

Since every state had its own mint and its own monetary system, transferring money through banks involved calculating the relevant rates of exchange, notably complicated by the fact that none of these monetary systems was decimalized. In addition, two different categories of money could come into play: ready money (money that also had a tangible existence as cash) and money of account (money that existed only on the books.)

In Florence around 1600, there were three kinds of money that could be used for transfers: the lira (divided into 20 soldi or 240 denari), the fiorino or ducato of 7 lire and the scudo d’oro of 7 1/2 lire. The lira existed as ready money; the fiorino/ducato of 7 lire corresponded to an actual value of ready money, the so-called piastra d’argento; the scudo d’oro of 7½ lire did not correspond to a value of ready money and existed only on account.

In the present document, we see the Depositeria Generale (the granducal fiscal administration) ordering the transfer of 235 scudi d’oro (235 scudi of account), 3 soldi and 10 denari to Venice. This sum corresponded to 1762 lire, 3 soldi and 10 denari di piccioli in Florentine ready money. One Venetian ducato (a gold-based money of account) was worth 79 1/6 per cent of a Florentine scudo d’oro. Therefore, 235.3.10 Florentine scudi equaled 297 1/12 Venetian ducati which in turn equaled 100 Spanish doble d’oro (doubloons), which was the money that Galileo in fact received for his services to the Medici.

ILLUSTRATION NOTES:

	Engraving by G. Villamena of "Galileo Galilei, Member of the Academy of the Lincei, Philosopher and Mathematician of the Most Serene Grand Duke of Tuscany."
Galileo Galilei, on an Italian 2,000 lire note (exchangeable until 28 February 2002 for 1.03 euros.)

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