The History of Irelan began with the first known human settlement in Ireland around 8000 BC, when hunter-gatherers arrived from Great Britain and continental Europe, probably via a land bridge. Few archaeological traces remain of this group, but their descendants and later Neolithic arrivals, particularly from the Iberian Peninsula, were responsible for major Neolithic sites such as Newgrange. Following the arrival of Saint Patrick and other Christian missionaries in the early to mid-5th century A.D., Christianity subsumed the indigenous pagan religion by the year 600.