Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often roughly divided into the Archaic period (9th to 6th centuries BC), Classical period (5th and 4th centuries BC), and Hellenistic period (Koine Greek, 3rd century BC to 4th century AD). It is preceded by Mycenaean Greek and succeeded by Medieval Greek. Koine is regarded as a separate historical stage although its earliest form closely resembles Attic Greek and its latest form approaches Medieval Greek. There were several regional dialects of Ancient Greek, of which Attic Greek developed into Koine. Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical periods of the language.