Every Mannerist worth his weight in papal commissions loves painting Mary Magdalene. Wake up, paint Mary Magdalene, repeat, that was the artist's watchword of the Renaissance. And it's not a Mary Magdalene painting if she's not half-dressed and brimming with repentance. If there was one thing Mary Magdalene loved, it was repenting. Wake up, repent of something, repeat, that was her watchword, presumably, if centuries-later paintings are anything to go by. In the Gospels themselves,…