He commenced his work with the broad assertion that Herodotus was "a liar," and was therefore bound to differ from him when he treated of the same periods or nations.

He does differ from him, and also from Thucydides, whenever they handle the same transactions; but in scarcely a single instance where he differs from either writer does his narrative seem to be worthy of credit.

The cuneiform monuments, while they generally confirm Herodotus, contradict Ctesias perpetually.

He is at variance with Manetho on Egyptian, with Ptolemy on Babylonian, chronology.

No independent writer confirms him on any important point.