Gwenllian ferch Gruffydd was born c.1100 in Aberffraw, Anglesey. And was a descendant of Brian Bóruma mac Cennétig, High King of Ireland. In 1113 she married Gruffydd ap Rhys (brother of Princess Nest and Prince of Deheubarth (Dyfed)). Gwenllian had three children, Morgan, Maelgwyn and Rhys, and lived at Dinefwr in Carmarthenshire.

Although initially privileged, Gwenllian’s family life was far from harmonious. Gruffydd’s rule was constantly challenged by the Normans and their family were often forced to seek refuge in mountains and forests or to lead counter- attacks on Norman strongholds in the county. Gwenllian’s father also formed an alliance with the English King and promised to kill his son-in-law. However, the couple were a powerful force who took possession of Carmarthen and Kidwelly castles for the Welsh.

It was perhaps Gruffydd’s confidence and/or hubris that led to Gwenllian’s downfall. He left his wife at Kidwelly to attack Ceredigion, but was defeated at Aberystwyth. This left Gwenllian vulnerable to capture and she was forced to flee alone into the forests.

Gwenllian and Gruffydd were eventually placed under surveillance in Carmarthen until the death of Henry I, when Gruffydd again left Gwenllian to travel to Gwynedd. It was at this point that the Norman leader, Maurice of London, seized his opportunity to attack Deheubarth, forcing Gwenllian to raise a defensive army of her own.

In 1136, during a fierce battle near Kidwelly Castle, the Welsh were defeated and Gwenllian saw her child Maelgwyn killed. She was subsequently captured and forced to kneel in view of her other son, Morgan, before being beheaded with a sword. It is said that her final words were ‘Cofiwch fi’ (‘remember me’). Morgan was also executed shortly afterwards.

Gwenllian’s courage has drawn comparisons with Boudicca, and her nomadic life with the legend of Robin Hood. Her legacy inspired others to revolt and her surviving child went on to become Lord Rhys, leader of Deheubarth and one of the most successful Welsh princes.

Ganed Gwenllian ferch Gruffydd tua 1100 yn Aberffraw, Ynys Môn. Roedd yn ddisgynnydd i Brian Bóruma mac Cennétig, Uchel Frenin Iwerddon. Yn 1113 priododd Gwenllian â Gruffydd ap Rhys (brawd y Dywysoges Nest a Thywysog y Deheubarth (Dyfed)). Roedd gan Gwenllian dri o blant, Morgan, Maelgwyn a Rhys, ac roedd yn byw yn Dinefwr yn Sir Gaerfyrddin.

Er ei bod o deulu breintiedig, roedd bywyd teuluol Gwenllian ymhell o fod yn ddidrafferth.  Roedd teyrnasiad Gruffydd yn cael ei herio’n gyson gan y Normaniaid ac yn aml fe orfodwyd eu teulu i geisio lloches yn y mynyddoedd a’r coedwigoedd neu i arwain gwrth-ymosodiadau ar gadarnleoedd y Normaniaid yn y sir. Hefyd roedd tad Gwenllian wedi ffurfio cynghrair gyda Brenin Lloegr ac addawodd ladd ei fab-yng-nghyfraith. Serch hynny, roedd Gwenllian a Gruffydd yn ŵr a gwraig grymus a lwyddodd i feddiannu cestyll Caerfyrddin a Chydweli i’r Cymry.

Efallai mai hyder a/neu falchder Gruffydd a arweiniodd at gwymp Gwenllian. Gadawodd ei wraig yng Nghydweli er mwyn ymosod ar Geredigion, ond fe’i trechwyd yn Aberystwyth. Gadawodd hyn Gwenllian yn agored i gael ei chipio a bu’n rhaid iddi ffoi ar ei phen ei hun i’r coedwigoedd. 

Cafodd Gwenllian a Gruffydd eu rhoi dan oruchwyliaeth yng Nghaerfyrddin tan farwolaeth Harri I, pan adawodd Gruffydd Gwenllian unwaith yn rhagor i deithio i Wynedd. Dyma’r adeg y gwnaeth yr arweinydd Normanaidd, Maurice o Lundain achub ar y cyfle i ymosod ar y Deheubarth, gan orfodi Gwenllian i godi byddin amddiffynnol ei hun.

Yn 1136, yn ystod brwydr ffyrnig ger Castell Cydweli, trechwyd y Cymry a gwelodd Gwenllian ei phlentyn Maelgwyn yn cael ei ladd. Cafodd hithau ei dal wedyn a’i gorfodi i benlinio gerbron ei mab arall, Morgan, cyn cael ei phen wedi’i dorri i ffwrdd â chleddyf. Dywedir mai ei geiriau olaf oedd ‘Cofiwch fi’. Dienyddiwyd Morgan yn fuan wedyn.

Mae dewrder Gwenllian wedi’i gyffelybu â Boudicca, a’i bywyd crwydrol gyda’r cymeriad chwedlonol Robin Hood. Roedd ei dewrder wedi ysbrydoli eraill i wrthryfela a daeth ei hunig fab a oroesodd yn Arglwydd Rhys, arweinydd y Deheubarth ac un o dywysogion mwyaf llwyddiannus Cymru.