The Histories of Herodotus is considered one of the seminal works of history in Western literature. Written from the 450s to the 420s BC in the Ionic dialect of classical Greek, The Histories serves as a record of the ancient traditions, politics, geography, and clashes of various cultures that were known in the Mediterranean and Asia at that time. It is not an impartial record but it remains one of the West's most important sources regarding these affairs. Moreover, it established without precedent the genre and study of history in the Western world, although historical records and chronicles existed beforehand. Perhaps most importantly, it stands as one of the first, and surviving, accounts of the rise of the Persian Empire, the events of, and causes for, the Greco-Persian Wars between the Achaemenid Empire and the Greek city-states in the 5th century BC. Herodotus portrays the conflict as one between the forces of slavery (the Persians) on the one hand, and freedom (the Athenians and the confederacy of Greek city-states which united against the invaders) on the other. It is to be noted that irony informs this account, for at around the time that Herodotus was writing and researching his book, Athens was an imperialist Greek empire in its own right (see the prelude in the article Peloponnesian War).