Hywel ap Rhys ('Hywel son of Rhys') (ruledc. 840–886) was aking ofGlywysing (either in part or in its entirety) in SouthWales.
His sons Arthfael andOwain were probably responsible for the reünification of the realm ofMorgannwg.[1] His grandsons, Owain's sons,Gruffydd ab Owain (died c. 935 at the hands of troops from Ceredigion) andCadwgan ab Owain (died c. 949 0r 951, "murdered by the Saxons") ruled as jointkings ofGlywysing from c. 930 until their deaths, before the surviving brotherMorgan Hen ab Owain (d. 974),[2] having previously ruled asKing of Gwent, brought the territories together under him as the Kingdom of Morgannwg.[3]

A cross in the collection of ancient stones atSt Illtyd's Church,Llantwit Major has been identified with Hywel. TheHouelt Cross has a Latin inscription written inhalf-uncial Latin which has consistently been interpreted as a memorial cross raised by Hywel for his father.
R. A. Stewart Macalister read the inscription as:
"NINOMINEDIPATRISE/TS | PERETUSSANTDIANC | --]UCEMHOUELTPROPE | --]BITPROANIMARESPA | --]ESEUS"
In 1950Victor Erle Nash-Williams translated it as "In the Name of God the Father and of the Son and of the Holy Spirit. This cross Houelt (PN) prepared for the soul of Res (PN) his father" while in 1976 theRoyal Commission on the Ancient and Historical Monuments of Wales translated it as "In the name of God, the Father and the Holy Spirit, Houelt (PN) prepared this cross for the soul of Res (PN) his father".[4]
The Cross itself is a striking example of aCeltic wheel cross and features interlacing carvings, and the work is a lasting reminder of Hywel's wealth and influence.[5]