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.
Old Assyrian Empire
The emergence of the Mitanni c. 1500 BC eventually led to a short period of sporadic Mitanni domination c. 1450 BC. The Indo-European-language-family-speaking Mitanni are thought to have conquered and formed the ruling class over the indigenous Hurrians in eastern Anatolia. The Hurrians had spoken a language isolate, one neither of the Afroasiatic language family nor the Indo-European language family.) There are dozens of Mesopotamian cuneiform texts from this period, with precise observations of solar and lunar eclipses, that have been used as "anchors" in the various attempts to define the chronology of Babylonia and Assyria between c. 2000 BC – c. 1300 BC.)