The story begins with Gwenllian's birth at Abergwyngregyn on the southern shore of the Menai Straits.  Across the straits in Anglesey, her mother, grandmother and great grandmother lie buried in the Franciscan Priory at Llanfaes.

 As a baby, Princess Gwenllian was taken to the Gilbertine Priory at Sempringham in Lincolnshire at the command of Edward I. She remained there until her death on the 7th June, 1337.

 Her memory had almost vanished from  history but in recent years her story has captured the imagination of the people of Wales and of Lincolnshire where she is now commemorated at Sempringham by a memorial hewn out of Penmaenmawr granite.

 Ganed Gwenllian ger Abergwyngregyn ar lannau deheuol y Fenai ac ar draws y
 Fenai ym Mhriordy'r Brodyr Ffransis, Llanfaes, Môn, gorwedd llwch ei mam, ei nain a'i hen nain.

 Yn faban bach, cludwyd y Dywysoges Gwenllian i Briordy Gilbertine, Sempringham, Swydd Lincoln, ar orchymyn Edward I.  Yno y bu hi am weddill ei hoes a bu farw 7 Mehefin 1337.

 Diflannodd y côf amdani, mwy neu lai'n llwyr, o dudalennau hanes.  Ond yn ddiweddar, cydiodd ei stori yn nychymyg, nid yn unig pobl Cymru ond hefyd yn nychymyg trigolion Swydd Lincoln ac erbyn hyn ceir carreg goffa iddi yn Sempringham wedi'i naddu o wenithfaen Penmaenmawr.