Catrin ferch Owain Glyndŵr
Catrin ferch Owain Glyndŵr( died 1413) was one of the daughters( probably the eldest) of Margaret Hanmer and Owain Glyndŵr, and her marriage to a claimant on the English throne was used by her father to gain support.
Gruffydd ap Llywelyn
Gruffydd ap Llywelyn( died 5 August 1063) was the King of Wales from 1055 to 1063.
He was the son of King Llywelyn ap Seisyll and Angharad, daughter of Maredudd ab Owain.
He was the great- great- grandson of Hywel Dda.
Cynan ap Hywel
Cynan ap Hywel( ruled 999–1005) was a Prince of Gwynedd, one of the kingdoms or principalities of medieval Wales.
He was the son of Hywel ap Ieuaf, a previous king from the line of Idwal Foel( his grandfather).
On Hywel's death, the realm was ruled by his brother, but almost immediately was seized by Maredudd ab Owain.
After the death in 999 of Maredudd, the rule of Gwynedd returned to the original dynasty in the form of Cynan ap Hywel.
Cynan reigned until 1005 but very little has been recorded about his reign, and nothing is known about the circumstances in which he was supplanted by Aeddan ap Blegywryd, who was apparently out of the direct line of succession.
Alys ferch Owain Glyndŵr
Alys ferch Owain Glyndŵr was one of the daughters of Margaret Hanmer and Owain Glyndŵr, the disinherited prince of the old Welsh royal house of Powys Fadog, who led a major revolt in Wales between 1400 and ca. 1416 against King Henry IV of England.
Little is known about any of the children of Owain Glyndŵr.
Owen Tudor
Sir Owen Tudor (1400 – 2 February 1461) was a Welsh courtier and the second husband of Catherine of Valois (1401–1437), widow of King Henry V of England.
He was the grandfather of Henry VII, founder of the Tudor dynasty.
Owen was a descendant of a prominent family from Penmynydd on the Isle of Anglesey, which traces its lineage back to Ednyfed Fychan (d. 1246), a Welsh official and seneschal to the Kingdom of Gwynedd.
Tudor's grandfather, Tudur ap Goronwy, married Margaret, daughter of Thomas ap Llywelyn ab Owain of Cardiganshire, the last male of the princely house of Deheubarth.
Margaret's elder sister married Gruffudd Fychan of Glyndyfrdwy, whose son was Owain Glyndŵr.
Owen's father, Maredudd ap Tudur, and his uncles were prominent in Owain Glyndŵr's revolt against English rule, the Glyndŵr Rising.
Maredudd ab Owain Glyndŵr
Maredudd ab Owain Glyndŵr was a son of Margaret Hanmer and Owain Glyndŵr.
He was the last significant active participant in the revolt raised by Glyndŵr in Wales between 1400 and c.1416.
Maredudd ab Owain ab Edwin
Maredudd ab Owain ab Edwin( died 1072) was a prince of the kingdom of Deheubarth in south west Wales.
Maredudd was the son of Owain ab Edwin and was hence the male- line heir of Hywel Dda.
The throne had been seized from the previous king of this line- Hywel ab Edwin- by Gruffydd ap Llywelyn, who claimed the throne through his mother, Angharad.
Angharad was the daughter of Maredudd ab Owain ap Hywel, while Hywel claimed the throne through the latter Maredudd's younger brother, Einion( Hywel's grandfather).
Gruffydd had united almost all Wales under his rule, and was the only ruler to be King of Wales, but on Gruffydd's death in 1063 Maredudd reclaimed Deheubarth for his line.
During Maredudd's reign the Normans sacked south- east Wales in response to welsh support for saxon revolts like that of Eadric the Wild.
After a few attempts to halt this, Maredydd decided not to resist the Norman encroachment on Gwent and was rewarded with lands in England in 1070.
In 1072 he was killed in a battle by the river Rhymni.
He was succeeded by his brother, Rhys ab Owain, rather than his young son, Gruffydd ap Maredudd.
When Rhys ab Owain died, the realm was seized by Rhys ap Tewdwr( Maredudd's second cousin, descended from a younger son of Einion).
Gruffydd lived on his father's lands in England for some years during this period, before being killed when trying to recapture his father's kingdom from Rhys ap Tewdwr.
Ieuan ab Owain Glyndŵr
Ieuan ab Owain Glyndŵr was reputedly the illegitimate son of the last native Welsh Prince of Wales; Owain Glyndŵr.
The possibility of his existence was uncovered through the work of Peter Bartrum which is currently being edited by the University of Wales Aberystwyth.
Ieuan ab Owain and his descendants are detailed in" Peniarth Manuscript 287" in the hand of Robert Vaughan of Hengwrt( c.1592-1667) and also in the manuscript known as" Harley 1969" by Griffith Hughes( 1634 – 1665)- the original manuscripts are kept at the National Library of Wales, Aberystwyth and the British Library respectively.
Ieuan, who is thought to have been born around 1380 and to have died around 1430, is thought to have had three sons:
Owain Glyndŵr
Owain ab Gruffydd, lord of Glyndyfrdwy (c. 1359 – c. 1415), or simply Owain Glyndŵr or Glyn Dŵr
(anglicized to Owen Glendower), was a Welsh leader who instigated a fierce and long-running yet ultimately unsuccessful war of independence with the aim of ending English rule in Wales during the Late Middle Ages.
He was the last native Welshman to hold the title Prince of Wales ("Tywysog Cymru").
Glyndŵr was a descendant of the Princes of Powys through his father Gruffudd Fychan II, hereditary "Tywysog" of Powys Fadog and Lord of Glyndyfrdwy, and of those of Deheubarth through his mother Elen
ferch
Tomas
ap Llywelyn ab Owen.
On 16 September 1400, Glyndŵr instigated the Welsh Revolt against the rule of Henry IV of England.
The uprising was initially very successful and rapidly gained control of large areas of Wales, but it suffered from key weaknesses – particularly a lack of artillery, which made capturing defended fortresses difficult, and of ships, which made rebel-controlled coastlands vulnerable.
The uprising was eventually suppressed by the superior resources of the English.
Glyndŵr was driven from his last remaining strongholds in 1409, but he avoided capture; the last documented sighting of him was in 1412.
He twice ignored offers of a pardon from his military nemesis, the new king Henry V of England, and despite the large rewards offered, Glyndŵr was never betrayed to the English.
His death was recorded by a former follower in the year 1415.
With his death
Owain acquired a mythical status along with Cadwaladr, Cynan and Arthur as a folk hero awaiting the call to return and liberate his people.
In William Shakespeare's play "Henry IV, Part 1", the character of Owen Glendower is a wild and exotic king ruled by magic and emotion.
In the late 19th century, the Cymru Fydd movement recreated him as the father of Welsh nationalism.
Rhain the Irishman
Rhain was an 11th- century king of Dyfed.
It is unclear when his reign began.
He claimed to be the son of Maredudd ab Owain and was apparently accepted as such by the people of Dyfed and the anonymous author of the C text of the" Annals of Wales".
However, after his defeat at Abergwill and deposition by Llywelyn ap Seisyll of Gwynedd in 1022, he was recorded by the other histories of the time as Rhain the Irishman( Welsh) and treated as a pretender.
The B text of the Welsh annals asserted he was killed in the battle with Llywelyn; the" Chronicle of the Princes", however, pointedly notes that his body was not discovered.

Question: Who is Maredudd Ab Owain Glyndŵr's paternal grandfather?
Answer: Gruffudd Fychan II