ProfessorR writes:
Socrates was put to death for his "unbelief in gods," even though he kept repeating that he believed in a God, just not quite the way the accepted Greek sacred writings taught.
Remember the political context of the trial: Socrates had been the teacher for many of the 30 Tyrants (including their leader, Critias, a cousin of Plato). The Tyrants are overthrown and Socrates is put out of the picture permanently a few years thereafter. He was accused by at least one man who was exiled by the Tyrants (little is known about the other two). I would be hesitant to draw a purely religious motivation in this case. How often did death for not worshiping the state religion happen in Athens?
Also, a book I am reading right now is The Battle For God by Karen Armstrong. She examines religious "fundamentalism" in the Abrahamic religions to the period of the Renaissance to the present day. The people in this topic might be interested by it.
Chris