ONE hundred and fifty years ago the Swiss art lover and historian Jacob Burckhardt published his master work, The Civilisation of the Renaissance in Italy. I believe this anniversary is as important as last year's of Darwin's On the Origin of Species. These two great 19th-century books are still at the living heart of their subjects. The study of the Renaissance can no more forget Burckhardt than biology can leave Darwin behind.

Both classics began in journeys. Darwin sailed to the Galapagos; Burckhardt merely went to Italy. His book drips with love of Italy and Italians. It is, among other things, one of the most passionate homages ever paid by a northern European to southern Europe, and yet herein lies its strangeness. Northerners, from Thomas Mann in Death in Venice to Martin Amis picturing the gilded English young on holiday in a southern castle in The Pregnant Widow, have tended to imagine Italy as a languorous, sleepy, timeless and archaic place — the slow, hot unconscious of the European continent, drooping out into the Mediterranean like a surrealist appendage.

Burckhardt saw things very differently. The fascination of reading his book is its vision of Italy as the birthplace of modern individualism, political calculation, science and scepticism. In 1860 Burckhardt looked at Italy and saw the shock of the new, secreted in sleepy ruins.

The ruins, at that moment, were becoming less sleepy. Italian cities were discovering art history as a commodity. Burckhardt, who studied history in Berlin before returning to work as a journalist and university teacher in his native Basel, was very much part of the 19th-century discovery of Italy by the bourgeoisie.

His book The Cicerone — a cicerone was an early tour guide — offered travellers a practical account of Italy's aesthetic riches. Where 18th-century aristocrats on their grand tours had seen themselves as lineal descendents of Roman senators and admired the classical tradition as their own, eternally connecting men of taste across the millennia, the women and men of the new middle classes of the industrial age were more alive to the otherness, the exotic sensuality, the mystery of the paintings and sculptures they travelled to Italy to see.

It is hard for us to comprehend the rapture these Victorians in their frock coats and high-collared dresses felt in front of the nudity of David. To get a sense of the obsession of 19th-century culture with Renaissance Italy, you only have to look up the name Savonarola in the British Library's digital catalogue. Today, this Ferrarese friar who exerted a charismatic grip on Florentine politics in the 1490s is studied by historians, but is no longer a household name. In the 19th century, by contrast, novels, plays and popular biographies of Savonarola streamed off the presses — books for the many, not the few. One that has endured is George Eliot's Romola (1862-63). To read this novel is to get some insight into the allure of the Renaissance for Victorians.

In 1860 there was not yet any agreed corpus of Renaissance art, so at the Uffizi you could gaze on Leonardo da Vinci's shocking painting of the Medusa — sadly now exiled from his oeuvre.

There were none of today's legions of curators and scholars arguing over the attribution of works. The Civilisation of the Renaissance in Italy would ignite the spark of art history as an academic subject — but its greatness as a book lies in its imaginative intoxication. It is not a critique, but the supreme expression of the 19th-century fantasy of the Italian Renaissance.

— The Guardian, London