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.
Hurrians
The Assyrian Empire collapsed from 620 to 605 BCE, after a series of brutal internal civil wars weakened it to such an extent that a coalition of its former vassals; the Medes, Persians, Babylonians, Chaldeans, Scythians and Cimmerians were able to attack and gradually destroy it. Urartu was ravaged by marauding Indo-European speaking Scythian and Cimmerian raiders during this time, with its vassal king (together with the king of neighbouring Lydia) vainly pleading with the beleaguered Assyrian king for help. After the fall of Assyria, Urartu came under the control of the Median Empire and then its successor Persian Empire during the 6th century BCE. During the 2nd millennium BC a new wave of Indo-European speakers migrated over the Caucasus into Urartian lands, these being the Armenians. It is argued on linguistic evidence that proto-Armenian came in contact with Urartian at an early date (2nd millennium BC), before the formation of the Urartian kingdom. In the 6th century BCE the region became part of the Armenian Orontid Dynasty. The Hurri-Urartians seem to have disappeared from history after this, almost certainly being absorbed into the Indo-European Armenian population.