The King taking a Bath ...
He is naked because he is pure, the cauldron is maybe a crucible, the Egg, Physical or/and Philosophical, the sword is the Secret Fire, associated to the Virgin Milk (a Knife in french is "une arme blanche" blanc = white, and a milk is white, and Knight and Knife are very close in English, the principal attribute of a Knight in stories, are that he kills the Dragon, and delivers the princess, so he is the Secret Fire, giving 'birth' to virginity of the matter = princess), the crossed sphere represent several thing, first, Antimony, or the World, "Malkuth" in kabbalah, it can also be the perfected world, or the Philosopher Stone. If so, here we are after the production of the Stone, and thus, the king is vulgar Gold, this is the Fermentation process.
This image was reproduced from Isaac Hollandus 'the hand of the Philosophers" 1667 Vienna.
Another lovely piece of Art. That you can find here