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.
Greek Dark Ages
The Greek Dark Ages, Homeric Age (named for the fabled poet, Homer) or Geometric period (so called after the characteristic Geometric art of the time), is the period of Greek history from the end of the Mycenaean palatial civilization around 1100 BC to the first signs of the Greek poleis, city states, in the 9th century BC.