It's a dead man in a bathtub. He is (or rather was) writing a note with a quill. It could look as if he commited suicide by slitting his wrists in the bath, and there's a knife on the floor and a letter in his hand, but he was in fact murdered. He's bleeding, the water stained red with blood, and he's still holding on to his feather pen.

The death of Marat

Wikipedia says: "The Death of Marat (French: La Mort de Marat or Marat Assassiné) is a painting by Jacques-Louis David of the murdered French revolutionary leader Jean-Paul Marat. It is one of the most famous images of the Revolution. David was the leading French painter, as well as a Montagnard and a member of the revolutionary Committee of General Security. The painting shows the radical journalist lying dead in his bath on 13 July 1793 after his murder by Charlotte Corday. Painted in the months after Marat's murder, it has been described by T. J. Clark as the first modernist painting, for "the way it took the stuff of politics as its material, and did not transmute it".

I had a lot of trouble finding this old, classical oil painting on google image search, so this page serves to include additional search terms for anyone in the same situation: It's a dead man in a bathtub. He is (or rather was) writing a note with a quill. It could look as if he commited suicide by slitting his wrists in the bath, and there's a knife on the floor and a letter in his hand, but he was in fact murdered. He's bleeding, the water stained red with blood, and he's still holding on to his feather pen.