The history of what is now Wales begins with evidence of a Neanderthal presence from at least 230,000 years ago, while Homo sapiens arrived by about 31,000 BC. However, continuous habitation by modern humans dates from the period after the end of the last ice age around 9000 BC, and Wales has many remains from the Mesolithic, Neolithic, and Bronze Age. During the Iron Age the region, like all of Britain south of the Firth of Forth, the culture had become Celtic, with a common Brittonic language. The Romans, who began their conquest of Britain in AD 43, first campaigned in what is now northeast Wales in 48 against the Deceangli, and gained total control of the region with their defeat of the Ordovices in 79. The Romans departed from Britain in the 5th century, opening the door for the Anglo-Saxon settlement. Thereafter, the culture began to splinter into a number of kingdoms. The Welsh people formed with English encroachment that effectively separated them from the other surviving Brittonic-speaking peoples in the early middle ages.

The Kingdom of Gwynedd was a Welsh kingdom and a Roman Empire successor state that emerged in sub-Roman Britain in the 5th century during the Anglo-Saxon settlement of Britain.