The vivid colours of a seductive reflection

In Medici Money , the novelist and essayist Tim Parks paints for us the ascent and the fall of the quintessential Florentine family with the sensitive touch and confident strokes of a foreigner who has adopted Italy as his physical and spiritual home.

I must confess that I was in a condescending mood when I first approached this book. A long time ago, I had read Raymond de Roover's The Rise and Decline of the Medici Bank 1397-1494 (1963), which left a lasting impression on me. It even helped me to shape my view of banking risk and develop a framework to manage it in a way that has profoundly marked me throughout my professional life. I thought that de Roover had said all there was to say about the Medici. Indeed, Parks quotes him with reverence at least three times in his own text.

But I was mistaken. Parks brings the Medici, their friends and their opponents vividly to life. Economically yet effectively he portrays the bigotry and brutality of the time as being not in contrast to but rather on a continuum with the deep religious faith, the artistic creativity and the superb mastery of the crafts.

Parks reproduces in full Song of the Peasants by Lorenzo de Medici, who ruled Florence from 1469 to 1478, and gives readers a concise explanation. "Lorenzo seduced his less educated Florentine subjects with rhyming obscenities. Everyone agreed he was a genius."

Perhaps not so much a genius as an early pornographer of great success. Not bad for a man who adorned churches and supported political parties. (Does this bring to mind any modern equivalent?) More seriously, Parks shows with the brevity and clarity of a scientist how a benign dictatorship could co-exist with the pretence of a democracy without either the corrupted or the corrupters feeling particularly stained by the whole experience.

Medici Money explores the past, but it has important lessons for today: in a healthy society, political power and financial power must confront each other dialectically, not collude. Collusion is bad for society, and is bad for the economy. Monopoly is bad not only for consumers, it is ultimately bad for the monopolists themselves. When religion steps unnecessarily into Caesar's field of competence, both God's chosen and Caesar suffer.

Consider the modern parallels in this statement: "A more neutral, less pro-Medici signoria introduced a property tax that seriously threatened the interests of the rich. Cosimo (the first of the Medici dynasty) put on a brave face and said he approved of the tax. It was important for him to have the support from the lower orders. His fellow travellers were not so pleased. Prominent men were having to sell property to pay the tax." Which is the more "politically correct": 15th-century Florence or 21st-century France, where even the conservative Right does not dare to scrap the wealth tax, which has caused a net tax loss to the French Exchequer?

The mechanisms that shaped Florentine finance work over and over again. "Meanwhile, other Florentine banks were going under altogether. In the mid-1420s, there had been 72; in 1470, there were only 33, with a half-dozen failures in the mid-1460s around the time Piero (the eldest son of Lorenzo) was calling in loans." Banking concentration is in progress, then one major player pulls in the oars and the credit crunch precipitates concentration no longer by merger, but by collapse of the weakest.

Parks is neither pedagogic nor prescriptive. He leaves the reader to join the dots and understand the picture for themselves. He is not a historian or a moralist, but he tells a powerful tale that is well-rooted in competent history and bears a strong moral message just beneath the surface.

This is not a book for specialists, it is a book that every educated person could give to a good friend as a birthday present - and that will provide the giver and the receiver enough conversation material to last through the winter nights. My recommendation: buy it.

Rudi Bogni is a former investment and private banker who is currently a corporate director and foundation trustee.