Hadean
The Hadean () is a geologic eon of the Earth pre-dating the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the ICS, 4 billion years ago. , the ICS describes its status as ""informal"". Geologist Preston Cloud coined the term in 1972, originally to label the period before the earliest-known rocks on Earth. W. Brian Harland later coined an almost synonymous term, the "Priscoan period", from "priscus", the Latin word for "ancient". Other, older texts simply refer to the eon as the Pre-Archean.
History of Western civilization before AD 500
The earliest urban civilizations of Europe belong to the Bronze Age Minoans of Crete and Mycenaean Greece, which ended around the 11th century BC as Greece entered the Greek Dark Ages. Ancient Greece was the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. Classical Greece flourished during the 5th to 4th centuries BC. Under Athenian leadership, Greece successfully repelled the military threat of Persian invasion at the battles of Marathon and Thermopylae. The Athenian Golden Age ended with the defeat of Athens at the hands of Sparta in the Peloponnesian War in 404 BC.