Who wrote about the Peloponnesian War?
The principal contemporary historian was Thucydides, who wrote a very reliable account. His work ended in 411 BCE, and the remainder of the war was taken up, apparently seamlessly, by Xenophon. However comparison of this account with other sources shows that it is flawed and often unreliable. Later secondary historians include Diodorus Siculus, whose accounts are generally extremely unreliable.