Context: Ystrad Tywi (English: "Vale of [the river] Tywi") is an area of south-west Wales situated on the banks of the Tywi river as it approaches the sea to join the Bristol Channel at Carmarthen. Although Ystrad Tywi was never a kingdom itself, it was a valuable territory and was fought over by the various kings of Dyfed, Deheubarth, Seisyllwg, the Kingdom of Gwynedd, the Kingdom of Morgannwg and the Normans. The area now makes up most of the modern county of Carmarthenshire.
History.
At the start of the 8th century Ystrad Tywi was part of the kingdom of Dyfed. Around the year 730 Seisyll ap Clydog, king of Ceredigion, captured Ystrad Tywi from Rhain ap Cadwgan, king of Dyfed, and annexed it to his own kingdom. The name Seisyllwg was given to the new enlarged kingdom., Hywel Dda or Hywel ap Cadell (c.880  950) was a King of Deheubarth who eventually came to rule most of Wales. He became the sole king of Seisyllwg in 920 and shortly thereafter established Deheubarth, and proceeded to gain control over the entire country from Prestatyn to Pembroke. As a descendant of Rhodri Mawr through his father Cadell, Hywel was a member of the Dinefwr branch of the dynasty. He was recorded as King of the Britons in the "Annales Cambriae" and the "Annals of Ulster"., Wales is a country that is part of the United Kingdom and the island of Great Britain. It is bordered by England to the east, the Irish Sea to the north and west, and the Bristol Channel to the south. It had a population in 2011 of 3,063,456 and has a total area of . Wales has over of coastline and is largely mountainous, with its higher peaks in the north and central areas, including Snowdon, its highest summit. The country lies within the north temperate zone and has a changeable, maritime climate., Gower or the Gower Peninsula (or ) is a peninsula in the south of Wales, projecting westwards into the Bristol Channel. It is the most westerly part of the county of Glamorgan, however it is currently administered as part of the unitary authority of Swansea. In 1956, Gower became the first area in the United Kingdom to be designated an Area of Outstanding Natural Beauty., The Kingdom of Dyfed is one of several Welsh petty kingdoms that emerged in 5th-century sub-Roman Britain in southwest Wales based on the former territory of the Demetae (modern Welsh "Dyfed"). Following the Norman invasion of Wales between 10671100, the region was conquered by the Normans and by 1138 incorporated into a new shire called Pembrokeshire after the Norman castle built in the Cantref of Penfro and under the rule of the Marcher Earl of Pembroke., Seisyllwg was a petty kingdom of medieval Wales. It is unclear when it emerged as a distinct unit, but according to later sources it consisted of the former Kingdom of Ceredigion plus the region known as Ystrad Tywi. Thus it covered the modern county of Ceredigion, part of Carmarthenshire, and the Gower Peninsula. It is evidently named after Seisyll, king of Ceridigion in the 7th or early 8th century, but it is unknown if he was directly responsible for its establishment. In the 10th century Seisyllwg became the center of power for Hywel Dda, who came to rule most of Wales. In 920 Hywel merged Seisyllwg with the Kingdom of Dyfed to form the new kingdom of Deheubarth., Llywarch ap Hyfaidd ( died c. 904 ) was a king of Dyfed in Wales of the High Middle Ages from c. 893 until its conquest around 904 by King Cadell of Ceredigion or Seisyllwg and his son Hywel . Upon Llywarch 's death , the kingdom passed briefly to his brother Rhodri , but Hywel soon consolidated his rule , eventually merging Dyfed with his paternal inheritance as the new kingdom of Deheubarth . Later Welsh tradition held that Hywel inherited Dyfed peacefully through his supposed marriage to Llywarch 's daughter Elen in a manner similar to the stories told about his great - grandfather Merfyn 's acquisition of Gwynedd , his grandfather Rhodri 's acquisition of Powys , and his father 's acquisition of Ceredigion , all of this despite female inheritance of land having no place in the Welsh law of the period . However , the repeated attacks of Cadell and Hywel were recorded in Asser 's Life of King Alfred , where it states Hyfaidd was ., A petty kingdom is a kingdom described as minor or "petty" by contrast to an empire or unified kingdom that either preceded or succeeded it (e.g. the numerous kingdoms of Anglo-Saxon England unified into the Kingdom of England in the 10th century, or the numerous Gaelic kingdoms of Ireland unified under the Kingdom of England as the Kingdom of Ireland in the 16th). Alternatively, a petty kingdom would be a minor kingdom in the immediate vicinity of larger kingdoms, such as the medieval Kingdom of Mann and the Isles relative to the kingdoms of Scotland or England or the Viking kingdoms of Scandinavia., Ceredigion is a county in Mid Wales. In the Middle Ages, it was a minor kingdom also known for a time as Seisyllwg. Following its Norman conquest, the name was anglicised to Cardigan and then Cardiganshire and it began to be administered as a county in 1282. The county had a population of 75,900 at the 2011 UK census. Its largest town, Aberystwyth, is one of the two administrative centres; the other being Aberaeron. Aberystwyth houses Aberystwyth University, Bronglais Hospital and the National Library of Wales. The inland town of Lampeter houses part of the University of Wales Trinity Saint David. More than half the population speak the Welsh language and the county is considered a centre of Welsh culture., Deheubarth (lit. "Right-hand Part", thus "the South") was a regional name for the realms of south Wales, particularly as opposed to Gwynedd (Latin: "Venedotia"). It is now used as a shorthand for the various realms united under the House of Dinefwr, but that Deheubarth itself was not considered a proper kingdom on the model of Gwynedd, Powys, or Dyfed is shown by its rendering in Latin as "dextralis pars" or as "Britonnes dexterales" ("the Southern Britons") and not as a named land. In the oldest British writers, "Deheubarth" was used for "all" of modern Wales to distinguish it from "Y Gogledd" or "Hen Ogledd", the northern lands whence Cunedda and the Cymry originated., Carmarthenshire (or informally "Sir Gâr") is a unitary authority in the south-west of Wales and is the largest of the thirteen historic counties of Wales. The three largest towns are Llanelli, Carmarthen and Ammanford. Carmarthen is the county town and administrative centre of Carmarthenshire, but the most populous settlement is Llanelli., The Kingdom of Ceredigion was one of several Welsh kingdoms that emerged in 5th-century post-Roman Britain. Its area corresponded roughly to that of the modern county of Ceredigion. The kingdom's hilly geography made it difficult for foreign invaders to conquer. Cardigan Bay bordered to the west. Ceredigion transparently means "the people of Ceredig." , Subject: llywarch ap hyfaidd, Relation: country_of_citizenship, Options: (A) british (B) england (C) hen ogledd (D) ireland (E) kingdom of dyfed (F) new kingdom (G) normans (H) roman britain (I) united kingdom (J) wales
Output: kingdom of dyfed