The Day the Universe Changed - James Burke [27]
5 units of cloth × 9 lire = 45 45÷7 = 6 lire The sum was usually done to show how the segments of the calculation related to each other:
This is essentially a rule of proportion, a pragmatic approach to calculation in a society where reckoning was done by eye, on the spot in the market-place.
The Italian of the late fifteenth century was familiar with the use of figures. He bought books about maths and made up games and jokes with it. He took measure of the world with a practised eye. This interest in numbers originated with the Greek philosophical cult started by Pythagoras, who believed that the mysteries of the universe could be penetrated and understood only through the use of magical numbers and their interrelationships. Florentines, reading his works for the first time, shared his view.
Modern Western music, beginning at this time in Italy, employed the Pythagorean scale. Using four strings of equal consistency, 6, 8, 9 and 12 inches long, the octave was produced, as well as its major divisions. The 6 and 12 inch strings were an octave apart, the 8 and 12 inch ones separated by a fifth. The 9 and 12 inch strings formed the fourth, and the 8 and 9 inch strings were separated by a single note. When people of the fifteenth century talked about ‘the music of the spheres’, or the mystical heavenly sounds of Aristotle’s universe, they meant it to be taken literally. Music and numbers were one and the same thing.
This society - numerate, superstitious, emotional, cruel and egotistic - was ideally placed to recover fastest from the economic devastation of the plague. Italy was sited exactly between northern Europe and the Near East. She took the products of the north - gold, grain, leather, wine, textiles - and carried them to the Black Sea and the Levant where they were exchanged for spices, silks, cotton and luxury goods in general. By the end of the fourteenth century the great Italian maritime republics of Genoa, Venice, Pisa and Livorno had bases all over the eastern Mediterranean, and there were regular departures for the Baltic.
What helped to give the Italians, and in particular the Florentines, control over these vast amounts of money and goods was their monopoly of the latest accounting system. Leonardo Fibonacchi, a Pisan who had been brought up in North Africa in what is now Algiers, had introduced the full range of Arab and Indian decimal calculation. The notation was called ‘letters of sand’, due to the original habit of on the spot calculation in a sand tray. Fibonacchi had also brought in a new Arab method of balancing income and expenditure. European accountancy at the time was a primitive affair. The merchant tended to treat each transaction as a separate entity. A paragraph giving details of the deal was followed by a space for later notes about costs, interest, sales, and so on. Little attempt was made to bring all transactions together into a comprehensive statement of budget. In the fourteenth century Fibonacchi’s double-entry system made a tentative appearance, first in Genoa and then in Venice. But it was the Florentines who were to take the most advantage of the system.
In 1397 the Medici family started lending money on an international scale. Others had tried it before. In the years before the Black Death the great Bardi, Peruzzi and Accaiuoli families had been bankrupted by the English and Neapolitan royal families who had defaulted on massive debts. But by the end of the fourteenth century the general economic recovery from the effects of the plague was demanding more flexible financial systems. The Medicis opened banks throughout Europe, providing a stable exchange rate, a regularity of service based on their branch managers’ ability to take independent decisions, and, above all, their efficient double-entry book keeping methods. Without these, the complex problem of a high level of cash flow coupled with varying exchange rates would have proved impossible to handle. The Medicis dominated the money market in Europe because they could balance their books.
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