THAT the Duomo in Florence was ever built is remarkable, given the man and his past.
Filippo Brunelleschi was a difficult genius with a flair for the spectacular, but there was the time during the siege of Lucca by the Florentines that he had diverted the Serchio River to flood the city and had catastrophically flooded his own troops.
Now he was demanding the right to build the largest self-supporting dome ever constructed - 138 ft across - on the cathedral of Santa Maria del Fiore in the heart of Florence. Most believed it was not possible and the committee appointed to vet the project was deeply sceptical, particularly as Brunelleschi would not tell them how he intended to perform the feat.
The story is told that at one of its endless meetings, the committee was told by the great man that he alone could stand an egg on its end. When they confessed they did not know how, he cracked the end.of the egg on the table and left it standing there. "But we could all have done that," they protested.
"Ah," Brunelleschi replied, what you would say if I told you how I intend to build the Dome." But they surrendered to him in 1420, and 15 years later the Duomo was inaugurated by the Pope.
There is a point to this story, and I'm coming to it. Brunelleschi's construction of one of the great wonders of the Renaissance world is celebrated in an important exhibition now showing only two streets away from the Dome in the renovated Palazzo Strozzi.
The exhibition, "Renaissance Engineers from Brunelleschi to Leonardo da Vinci", brought home to Florence from Paris to mark the European Council last weekend, is a breathtaking tribute to two generations of artist-engineers who embodied the rebirth of science and the emergence of a new type of rational, empirical thinking.
The exhibition has been designed to appeal to the child in all of us. The lure of the steam engine and linotype machine are the same - working innards on display, the elegance of deceptively simple-looking engineering.
Here, beside the silk screen blow-up prints of their machines for lifting, dredging, pulling, catapulting, diving, and even flying, are working models of the same. And computer animations of them appear as they might have been at work on that dome.
Brunelleschi designed not only the dome but the implements to build it, manually operated cranes, built around the shape of the building, which lifted every piece of the 37,000 tons of the dome through 50 metres and positioned the heavy blocks with extraordinary precision.
In the tiny, torn notebooks, page after page, brown with age, of Leonardo's anatomical drawing seem almost alive. Then there are the half-finished dissertations and carefully annotated drawings of every kind of screw or cam or gearing.
In other rooms, tribute is paid to the great Sienese engineers Taccola (1381-1458) and Franceso di Giorgio (1439-1501), experts in the water technology needed to make Siena's 25 kilometres of water tunnels, bottini. And perhaps most fun, di Giorgio's huge machines for lifting, moving and positioning columns and obelisks.
But the exhibition is much, more than a collection of ingenious machines: its real significance is as a contribution to our understanding of the evolution of science and particularly Leonardo's place in the Renaissance.
"From such a vantage point, Leonardo ceases to be a visionary prophet in the desert," writes Paolo Galluzzi of the University of Florence in the catalogue. "Rather he appears as the man who most eloquently expressed - both with words, and above all images - the utopian visions about the practical potential of technology that were enthusiastically shared by many `artist-engineers' of the 15th century."
Indeed, many of the inventions attributed to Leonardo are in fact shown to be reproductions of work done by brilliant predecessors. But such a perception, far from diminishing the achievement, simply puts his genius in a new perspective.
He is still the master of draughtsmen, visionary in the scope of his imagination and uniquely ahead of his time in his curiosity about the inner workings of machines and men - not to simply to depict them more accurately but to understand the laws that govern them.
But I should leave the last word to this "unlettered" man's salutary injunction to all writers: "Because of your lack of information, you write confusingly and give little notion of the true state of things..."
