Independent Wales was defined in the centuries after the Romans withdrew from Britain in 410 AD. The Welsh achieved this despite Irish and Viking raids and colonization, despite the growing power of the Anglo-Saxon kingdoms, and despite frequent and often bitter dissension between themselves. Part of the Tempus History of Wales series, this study analyzes the wars of Welsh independence that encompass centuries of raids, expeditions, battles, and sieges—from increased pressure from the east from the 11th century onwards to the ambitious and almost successful revolt under Owain Glyn Dwr in the 15th century.