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.
History of Hungary
The Iron Age commenced around 800 BC, associated with "Thraco-Cimmerian" artefact types, 
representing the overlap of the pre-Scythian (Novocherkassk culture) and pre-Celtic (Hallstatt culture) cultural spheres.
Hallstatt occupation of western Transdanubia is evident from about 750 BC Early Greek ethnography locates the Agathyrsi and the Sigynnae in the region.
By the 4th century BC, the Pannonian basin was occupied by Pannonians (assumed to be an Illyrian tribal confederation) and by Celts (Taurisci). Following 279 BC, the Celtic Scordisci after their defeat at Delphi, settled in southern Transdanubia. The northeastern part of the Carpathian basin was reached by the Boii in the 2nd century BC.