Why did medieval European alchemists paint the sun and the moon?

These paintings were mainly created during and after the Renaissance.

Renaissance art praised the beauty of the human body and advocated that the proportion of the human body was the most harmonious in the world, which reflected the humanistic thought of advocating individual liberation and opposing asceticism and religious views in the Middle Ages. In architecture, although a series of paintings and sculptures still focus on religious stories, they all show scenes of ordinary people, which affirm human rights, oppose theocracy and abandon all authority and traditional dogma as the basis of theology and scholasticism.

The naked human body directly shows the beauty of the human body and the rebellious spirit of human beings who want to get rid of bondage and pursue individual liberation. At the same time, it strongly impacted the feudal conservative medieval asceticism and religious views.

This is the most natural form of the human body.