The Greek cross temple idea

struck later popes as altogether too pagan.

A big long nave was added, the opposite of what Bromante

and Michelangelo had wanted.

But you still feel the essence

of his "Ingenio" beneath that dome.

Rising 120 metres above the ground, over 40 metres diameter,

the tallest dome in the world, taller than the dome

of the Suleiman mosque, taller than the Hagia Sophia,

The work of the man his biographers called Il Divino.

The divine one.

No-one would have quite dared to say that about Mimar Sinan.

But in Europe,

the cult of the superhero artist listening to his own voice,

which is to say the echo of God, rather than his patron,

had taken off.

Their lives were now for the first time

since antiquity the subject of page-turning biographies.

As fascinating, if not more so, than those of saints and kings.

For, often, they describe the work of sinners.

And among the gallery of self-described geniuses,

no-one sinned quite like the Florentine goldsmith

Benvenuto Cellini.

It was from house arrest for living in sin with a boyfriend

who shopped him to the authorities that Cellini wrote

his blood-soaked, chest beating thriller of an autobiography

which, aside from a catalogue of murders, prison escapes,

and gunfights, was one long document of yearning

to be treated as a true artist genius,

alongside his hero, Michelangelo.

Michelangelo knew Cellini and, in fact,

on at least one occasion, gave him a hearty endorsement,

but as the world's best goldsmith,

and, for Benvenuto, that was not going to be enough.

Only a bona fide genius, after all,

could have managed to turn a golden salt cellar

into a witty erotic sculpture.

But the godly form of Poseidon showed that Cellini

could make heroic figures with the best of them.

In Florence,

the bronze to beat was

Donatello's heroine from scripture, Judith,