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.
Mycenae
In the absence of documents and objects that can be precisely dated, events at Mycenae can only be dated relatively within the constraints of Helladic chronology which relies on categorisation of stratified material objects, mainly pottery, within an agreed historical framework. Mycenae developed into a major power during LHI (c. 1550–c. 1450 BC) and is believed to have become the main centre of Aegean civilisation through the fifteenth century to the extent that the two hundred years from c. 1400 BC to c. 1200 BC (encompassing LHIIIA and LHIIIB) are known as the Mycenaean Age. The Minoan hegemony was ended c. 1450 and there is evidence that Knossos was occupied by Mycenaeans until it too was destroyed c. 1370 BC. From then on, Mycenaean expansion throughout the Aegean was unhindered until the massive disruption of society in the first half of the eleventh century (LHIIIC) which ended Mycenaean civilisation and culminated in the destruction of Mycenae itself c. 1150 BC.