"The Death of Socrates" by David (1787)
Socrates was killed, forced to drink hemlock by the Athenian state, for running afoul of the new political regime. However, this was not a crime so what he was accused of was “corrupting the youth” and “impiety” by introducing new gods and not worshiping the gods of the state. Blasphemy basically.
What he did was introduce the idea of a daimonion (literally, a “divine something) sort of a guardian angel that warned him of danger but did not order him to do things. This “daimonion” usually came in signs and portents rather than as an actual being. It was described “a special being watches over each individual. Later this term for guardian angel became the basis for the English word “demon”.