AD 410-1066 Early Medieval

From the middle of the 4th century AD onwards the Roman army withdrew from Wales. Much of the trade and transport infrastructure which had been built by the Romans collapsed. The regional capital at Venta Silurum (Caerwent) declined, Roman roads disintegrated, mining ceased and trade was by barter and exchange instead of coinage. Wales began to develop existing sea routes to trade with Ireland, Gaul and the Mediterranean.

There are few written sources after the departure of the Romans, and events of the 5th and 6th centuries are unclear. It is sometimes difficult to distinguish between reality and legend. Wales developed into several kingdoms. At times energetic monarchs such as Rhodri Mawr (the Great) of Gwynedd and Hywel Dda (the Good) of Deheubarth extended their influence over much of Wales.

Hywel Dda was the first king to set down Welsh law in writing. By 950 he ruled most of Wales, and appears to have been regarded as a kind of overking. However Hywel was forced to submit to the Anglo-Saxon kings of Wessex and afterwards ruled under the authority of Athelstan, king of the English (reigned 927-939). In 1039 Gruffudd ap Llewelyn (died 1063) became king of Gwynedd. Under his forceful ambition, the kingdoms of Wales were, for a short time, united. However, after the Norman Conquest in 1066, Wales was once again pressured by the rulers of England.