Ancient Greece was a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity (ca. AD 600). Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in ancient Greece is the period of Classical Greece, which flourished during the 5th to 4th centuries BC. Classical Greece began with the repelling of a Persian invasion by Athenian leadership. Because of conquests by Alexander the Great of Macedonia, Hellenistic civilization flourished from Central Asia to the western end of the Mediterranean Sea. Classical Greek culture, especially philosophy, had a powerful influence on the Roman Empire, which carried a version of it to many parts of the Mediterranean Basin and Europe, for which reason Classical Greece is generally considered to be the seminal culture which provided the foundation of modern Western culture.