 Elsewhere it may last until the early centuries AD, and either Christianization or a new conquest in the Migration Period.Iron working was introduced to Europe in the late 11th century BC, probably from the Caucasus, and slowly spread northwards and westwards over the succeeding 500 years.For example, the Iron Age of Prehistoric Ireland begins around 500 BC, when the Greek Iron Age had already ended, and finishes around 400 AD.