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.
Helladic chronology
The Early Helladic period (or EH) of Bronze Age Greece is generally characterized by the Neolithic agricultural population importing bronze and copper, as well as using rudimentary bronze-working techniques first developed in Anatolia with which they had cultural contacts. The EH period corresponds in time to the Old Kingdom in Egypt. Important EH sites are clustered on the Aegean shores of the mainland in Boeotia and Argolid (Manika, Lerna, Pefkakia, Thebes, Tiryns) or coastal islands such as Aegina (Kolonna) and Euboea (Lefkandi) and are marked by pottery showing influences from western Anatolia and the introduction of the fast-spinning version of the potter's wheel. The large "longhouse" called a "megaron" was introduced in EHII. The infiltration of Anatolian cultural models (i.e. "Lefkandi I") was not accompanied by widespread site destruction.