Cryptic (geology)
The Cryptic era is an informal term for the earliest geologic evolution of the Earth and Moon. It is the oldest (informal) era of the Hadean eon, and it is commonly accepted to have begun close to 4533 million (about 4.533 billion) years ago when the Earth and Moon formed. No samples exist to date the transition between the Cryptic era and the following Basin Groups era for the Moon (see also Pre-Nectarian), though sometimes it is stated that this era ended 4150 million years ago for one or both of these bodies. Neither this time period, nor any other Hadean subdivision, has been officially recognized by the International Commission on Stratigraphy.
Kurdish calendar
Some claim that the Kurdish calendar starts at 700 BC; this was the year Deioces united the Medes according to Herodotus. However, the claim of unification by Herodotus is proven wrong. The Medes still were vassals of the Assyrian Empire. The Median kingdom and the founding of its capital city at Ecbatana (modern Hamadan) was probably not before 625 BC when Cyaxares (grandson of Deioces) succeeded in uniting the many Median tribes into a single kingdom. In 614 BC, he captured Ashur, and in 612, in an alliance with Nebuchadnezzar of Babylon, his forces stormed Nineveh, putting an end to the Assyrian Empire.