Glyndŵr, Owain ( Owain Glendower) (c.1359–c.1415), self-styled prince of Wales. A wealthy landowner in north-east Wales, his father was descended from princes of Powys and his mother from princes of Deheubarth. His rising (1400–10) was a serious and costly threat to the usurper Henry IV. Owain was a well-to-do gentleman, trained at the Inns of Court, serving in Richard II's armies against the Scots (1384–5), and becoming a retainer (by 1387) of the lord of Chirk, Richard Fitzalan, earl of Arundel. He married Margaret, daughter of Sir Edward Hanmer, a distinguished judge. By 1400 conditions in Wales were ripe for rebellion: there was racial tension between Welsh and English fanned by poets and propagandists; economic and social dislocation after the Black Death was made worse by the crown and English nobles exploiting their Welsh resources more harshly; and the Welsh church was dominated by an English hierarchy at the expense of Welsh priests. French meddling and encouragement from Scotland and Irish lords fed the resentment, and risings before 1400 (especially by Owain Lawgoch in the 1370s) were a foretaste of widespread unrest.

Glyndŵr took the lead partly because of personal grievances against Lord Grey of Ruthin and Henry IV. He was proclaimed prince of Wales by friends and relatives at Glyndyfrdwy (Merioneth) on 16 September 1400, and attacked Grey's estates and towns close to the English border. He relied on his kinsmen, especially the Tudors of Anglesey who captured Conwy castle (April 1401). Owain advanced into central and south Wales following a victory in the Plynlimmon mountains (1401); his capture of Lord Grey (April) and the uncle of Edmund Mortimer, earl of March and claimant to the English throne (22 June), was a political coup, especially when the captive Mortimer married Owain's daughter. Expeditions led by Henry IV (1400–3) achieved little, and Parliament (1401–2) panicked into passing legislation to curb the rights of Welshmen. Owain sought allies among other rebels, especially the Percy family and the earl of March's supporters, though Henry IV's victory at Shrewsbury (21 July 1403) was a set-back. Owain focused on south Wales, capturing several castles, as well as Aberystwyth and Harlech (1404). He negotiated the treaty of Paris with Charles VI of France (14 July 1404), and he ‘and his hill-men’ held assemblies at Machynlleth, Harlech, and Pennal (1404–6) where ambitious plans were laid for an independent principality. These included support for the Avignon pope, a Welsh church, university, and civil service, and a principality extending into the English midlands. Although French troops landed in Milford Sound to assist him, 1405–6 saw significant reverses, and his French and Percy allies faded away. Aberystwyth and Harlech capitulated in 1408, and Owain's wife and two daughters were captured. Following a raid in Shropshire in 1410, Owain disappeared; he refused a pardon from Henry V in 1415 and may have died soon afterwards.

Ralph Alan Griffiths