Titian

For a long time this was just filed as 'Portrait of a Man' — someone eventually managed to make out the barely-legible letter he's holding, addressed to himself, and that's apparently how they worked out who he was.

Apparently X-rays show he first painted the two of them sitting upright and stiff, almost like a formal icon, before loosening it into this warmer, cuddled-up pose.

They say experts spent decades arguing over who even painted this — one called it Giorgione, another said Palma il Vecchio — before most eventually came round to the name on the card now.

Apparently this is one of his earliest known paintings — from back when he was still learning from a couple of older Venetian painters.