The History of the Peloponnesian War is an account of the Peloponnesian War in Ancient Greece, fought between the Peloponnesian League (led by Sparta) and the Delian League (led by Athens) in the 5th Century BC. It was written by Thucydides, an Athenian general who served in the war. It is widely considered a classic and regarded as one of the earliest scholarly works of history. The History is divided into eight books. These book divisions are the work of editors in later antiquity.