Hellenica is one of the most important primary sources for the History of the Peloponnesian War and the war's aftermath. Many consider this a very personal work, written by Xenophon in retirement on his Spartan estate, intended primarily for circulation among his friends, for people who knew the main protagonists and events, often because they had participated in them. It covers the events in Greece from 411 to 362 BC, and is considered to be the continuation of the History of the Peloponnesian War by Thucydides.