 Little is known for certain concerning his philosophical views or the nature of his alleged atheism.All that is known for certain on the point is that Diagoras was offended by the worship of the Athenian national gods.Cicero, writing in the 1st century BC, tells of how a friend of Diagoras tried to convince him of the existence of the gods, by pointing out how many votive pictures tell about people being saved from storms at sea by "dint of vows to the gods", to which Diagoras replied that "there are nowhere any pictures of those who have been shipwrecked and drowned at sea."