Who is Thucydides from The Greek Way and what is their importance?

Thucydides was the historian of the Peloponnesian War (the war between Athens and Sparta) and of the period of Athenian supremacy following the war. One of the most notable in the historical writing of Thucydides was the notion that history repeats itself in cycles and will continue to do so until humans learn from the past and take action to prevent its recurrence. Also important was the conviction that greed for power and wealth are the root of all evil and the root cause of war.