Ystlyg () was a medieval

cantref A cantref ( ; ; plural cantrefi or cantrefs; also rendered as ''cantred'') was a Wales in the Early Middle Ages, medieval Welsh land division, particularly important in the administration of Welsh law. Description Land in medieval Wales was divid ...

in the

Kingdom of Powys The Kingdom of Powys (; ) was a Welsh successor state, petty kingdom and principality that emerged during the Middle Ages following the end of Roman rule in Britain. It very roughly covered the northern two-thirds of the modern county of Pow ...

. It lay at the east of the kingdom on the border with England. It consisted of the

commote A commote (, sometimes spelt in older documents as , plural , less frequently )'' Geiriadur Prifysgol Cymru'' (University of Wales Dictionary), p. 643 was a secular division of land in Medieval Wales. The word derives from the prefix ("together" ...

s (''cymydau'') of Deuddwr in the north, Ystrad Marchell in the centre, Llannerch Hudol (also written Llannerchwdwl, Llanerchydol or Llannerchudol) in the south, and Y Gorddwr (or Corddwr) in the east beyond the

River Severn The River Severn (, ), at long, is the longest river in Great Britain. It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of at Apperley, Gloucestershire. It rises in t ...

and

Offa's Dyke Offa's Dyke () is a large linear Earthworks (Archaeology), earthwork that roughly follows the England–Wales border, border between England and Wales. The structure is named after Offa of Mercia, Offa, the Anglo-Saxons, Anglo-Saxon king of Mer ...

. Ystad Marchell, Llannerch Hudol and Deuddwr formed the ''Teirswydd'' (English: three ommotes(literally, swydd is ''post'' as in an

office An office is a space where the employees of an organization perform Business administration, administrative Work (human activity), work in order to support and realize the various goals of the organization. The word "office" may also denote a po ...

)) which were among the lands restored into the possession of

Gruffydd ap Gwenwynwyn Gruffudd ap Gwenwynwyn (died c. 1286) was a Welsh people, Welsh king who was lord of the part of Kingdom of Powys, Powys known as Powys Wenwynwyn; he sided with King Edward I of England in the latter's Conquest of Wales by Edward I, conquest of W ...

in return for his homage and

fealty An oath of fealty, from the Latin (faithfulness), is a pledge of allegiance of one person to another. Definition In medieval Europe, the swearing of fealty took the form of an oath made by a vassal, or subordinate, to his lord. "Fealty" also r ...

Llywelyn ap Gruffudd Llywelyn ap Gruffudd ( – 11 December 1282), also known as Llywelyn II and Llywelyn the Last (), was List of rulers of Gwynedd, Prince of Gwynedd, and later was recognised as the Prince of Wales (; ) from 1258 until his death at Cilmeri in 128 ...

at Ystumanner in 1263. Y Gorddwr had remained under the control of the Corbet family (barons of Caus) and therefore the English king. The cantref of Ystlyg (excluding Y Gorddwr) corresponds to the later

hundred 100 or one hundred (Roman numerals, Roman numeral: C) is the natural number following 99 (number), 99 and preceding 101 (number), 101. In mathematics 100 is the square of 10 (number), 10 (in scientific notation it is written as 102). The standar ...

of Deuddwr.

References

{{reflist History of Powys Cantrefs