I had a quick peek at the excellent new Cranach exhibition at the Royal Academy this week. I didn't know much 
about Lucas Cranach the Elder before I went along -- except that he was one of those few painters whose work even an amateur like me could spot a mile off.
The Academy's Norman Rosenthal lumped him together with Modigliani and Botticelli for instant recognisability, which I thought was a bit unfair to Botticelli, but you know what he means.
This Cranach show had caught the headlines a few weeks ago when London Transport first of all banned his nude Venus advertising poster from the underground, then relented. So we can now see her on the tube in all her glory.
But seeing her in the flesh sprang a couple of surprises.
First of all, there is no good reason at all for giving this painting the title 'Venus'. She has no particularly Venus-like attribute ' no little Cupid for example. 'Venus'. it turns out, is a just a way of putting a bit of classical respectability onto this rather pert girl. We have no clue who she was, or was meant to be.
Secondly, she's very small, less than 40 cm by 25 cm. That's tiny compared with her bill-board appearance on the tube. In other words, in the original, she looks like a bijou piece of private, boudoir erotic art.
Would she have found it so easy to win her reprieve from London Transport if she'd been known as some rich man's mistress instead of the bona fide Roman goddess? Personally I'm very pleased to be able to catch sight of her smirking on the underground. But whoever it was who objected to her as porn 
had a point.
I also hadn't realised that 'Venus' had a pair: a small nude painting of the legendary Lucretia, who killed herself under the last king of Rome, Tarquin the Proud, after one of the king's relatives had forced her to sleep with him (whether it strictly counted as 'rape' or not exercised Roman and later commentators). It was this event that led to the overthrow of the early Roman monarchy ad the foundation of the Republic.
In this painting, she's in much the same pose as 'Venus', except that she is about to plunge a decidedly phallic dagger into her breast.
How different would our reactions have been if we had been confronted with this female victim of sexual violence, about to kill herself, accompanying our tube rides?