Every so often, the Virgin herself

would show up for the pilgrims.

But this is no provincial scene, is it?

Its appealing doorway in the backstreets of Rome,

the doorstep drama is lit by a great wash of light.

But the reason why one of the Caravaggio's critics

said the painting caused a great "Schiamazzo", a cackle,

was because so much flesh was on display.

This is a barefoot Madonna, not the spun sugar version

of conventional painting, but of real-life body,

probably Caravaggio's girlfriend.

And the adoration dwells on that sumptuous form -

the heavy lids, the glossy ropes of hair.

And the naked Christ Child is a squirmy bambino, fat with pasta.

And the poor pilgrim couple who kneel before them

are made bodily present too -

that big rump of the man,

those calloused feet from the long walk.

As in all the greatest Caravaggio's,

these big fleshy figures are uncomfortably,

almost disturbingly, close to us.

Caravaggio has broken right through the fourth wall

and he's done it in the

name of making the Christian message true.

By which he means physically true.

We don't get a kind of remote heavenly apparition that's granted

to us by the intercession of some priest.

No, we are physically in the company of the Madonna and Child,

just as much as if we are walking down the street and look round

and there they are, standing in a doorway.

And this, of course, is a breach in every kind of decorum,

social as well as aesthetic.

But breaking rules was what this generation of Western artists

was all about.

And the closer they got both to God and to kings,

paradoxically, the more freedoms they claimed.

And one of the most spectacular

of those rule breakers was a woman

in her 40s when she painted this in England -

Artemisia Gentileschi.