The Mortimer family came over to England from Normandy as part of the invading army of William the Conqueror, and c. 1075, one of the family, RALPH de MORTIMER, was granted certain lands in Shropshire and Herefordshire, with the castle and township of Wigmore in the latter county as focal point. It was from this beginning that the family eventually grew to be a dominant factor in Welsh border history. There are references to the first Ralph fortifying the castle of ‘Dinieithon,’ and conquering ‘Melenyth,’ both in modern Radnorshire. During the 12th century it appears, from the scattered references available, that there was much fighting between the Mortimers and the Welsh. In 1144 HUGH de MORTIMER reconquered Maelienydd and Elfael, this implying a previous conquest and loss, and in 1145 he captured the prince Rhys ap Hywel. He was also responsible for the death of Maredudd ap Madog ab Idnerth in 1146.
ROGER de MORTIMER was imprisoned for two years in 1179 owing to his followers having been involved in the death of Cadwallon ap Madog, and in 1191 he was banished for three years, this time on a charge of conspiring with the Welsh against the king. He returned in due course, and in 1195 drove Cadwallon's sons out of Maelienydd, but in 1196 he and Hugh de Say of Richard's castle were heavily defeated by Rhys ap Gruffydd near Radnor. In the first half of the 13th century Llewelyn ap Iorwerth became one of the most powerful princes in Wales, and in 1230 the Mortimers associated themselves with this prince when RALPH de MORTIMER married his daughter Gwladus Ddu. Their son, ROGER de MORTIMER, considerably extended the family's territorial possessions in Wales by his marriage in 1247 with Matilda, eldest daughter of William de Braose, formerly lord of Brecon. Matilda was also joint heir of the Marshal estates in right of her mother Eve, daughter of William Marshal, earl of Pembroke (see Marshal family). To the Mortimers, therefore, she brought a third of the great honour of Brecon, the lordship of Radnor, and lands in Carmarthenshire and Pembrokeshire. With such territorial accretions the family was now assuming a dominant position as marcher lords. Roger's great adversary in Wales was his kinsman, the Welsh prince Llewelyn ap Gruffydd. There was intermittent fighting and truce-making until both met their deaths in 1282. The struggle between marcher lord and Welsh prince became at this juncture merged in the larger contest between the barons and Henry III, and, later, in the campaigns of Edward I against Wales. In 1262 and 1266 Mortimer was heavily defeated by Llywelyn, and, in September 1267, by the Treaty of Montgomery, large portions of his land were surrendered to that prince. In November 1276 Mortimer was appointed captain for Shropshire, Staffordshire, and Herefordshire, and the adjoining districts, in Edward I's campaign against the Welsh. He was successful in wresting much land from his adversaries. During this time he was also extremely active in the king's service in judicial affairs. He died in 1282.
EDMUND de MORTIMER (died 1304) was constantly requested to take measures against the rebellion of Rhys ap Maredudd of Ystrad Tywi, 1287-88. His son, ROGER de MORTIMER, later 1st earl of March, combined with his powerful uncle Roger of Chirk, and made the family a major power in Welsh affairs. Fearing the influence of their great rivals, the Despensers, in South Wales, they sided with the earl of Hereford in his quarrel with the Despensers concerning the acquisition of Gower in 1321. They conducted a successful military campaign in South Wales, but in January 1321/2, having taken up arms against the king, they were defeated and imprisoned. With the accession of Edward III, however, Roger Mortimer of Wigmore enjoyed greater favour than ever. On 20 February 1326/7, he was appointed justice of Wales and of the bishopric of Llandaff during the king's pleasure. The latter office was renewed on 4 August 1328, and he was made justice of Wales for life on 27 August 1328. The appointment as justice of Wales was renewed on 4 November 1328, after his elevation to the earldom of March, and on the same day he was appointed justice in the bishopric of S. Davids for life. He had, in June 1327, been granted custody of the lands of ‘Glamorgan and Morganwg’ during the king's pleasure, and in September 1327 was granted lands worth £1,000 per annum, including the castle of Denbigh and the escheated lands of the earl of Arundel in Wales. His official position, allied to his great landed possessions, made him well-nigh supreme in Wales until his death in 1330, when he was executed as a traitor.
The next heir was the 1st earl's grandson, ROGER de MORTIMER (1327? - 1360), and he, in spite of his grandfather's treason, was gradually allowed to regain his estates in the Welsh March.
He died February 1359/60. During the remainder of the 14th century the family does not appear to have played any outstanding part in Welsh affairs. They, however, became connected with the rebellion of Owain Glyndŵr at the beginning of the next century. When Roger de Mortimer, 4th earl of March, died in 1398, his son, EDMUND, was still a minor, and consequently Roger's brother, also called EDMUND, became the most important representative of the family in the Welsh March. When the Glyndŵr rebellion broke out, he was associated with his brother-in-law, Henry Percy, in measures against the rebellion.
Captured by Glyndŵr in 1402, he, however, married his captor's daughter, Catherine, and entered boldly into his schemes. In the famous treaty of partition drawn up between Mortimer, Glyndŵr, and the earl of Northumberland, Mortimer was to receive the southern half of England. All, however, came to naught and Mortimer perished in the siege of Harlech castle, 1409? Edmund the nephew died 1425, and the estates now passed to Richard, duke of York, son of Anne Mortimer and Richard, duke of Cambridge.
Published date: 1959