When writing to the Pope, attempting to secure more money for Sempringham Priory from the Church, the English king stated that "...herein is kept the Princess of Wales, whom we have to maintain". The title "Princess of Wales" as used here did not have its usual accepted meaning. Having been taken from her native land so young, Gwenllian is unlikely to have remembered any Welsh she may have learned as a toddler, and perhaps never knew the correct pronunciation of her own name. The priory record-keepers listed her as "Wencilian" and was herself shown to have signed her name "Wentliane". Edward III of England, Edward I's grandson, endowed Gwenllian with a pension of £20 per year; this was not money for her personally, simply a sum paid on her behalf to the priory in respect of her food and clothing. Her death there was recorded by the priory's chronicler in June 1337, a few days before her 55th birthday. Dafydd's two young sons, heirs to the Principality or Kingdom of Wales, were taken to Bristol Castle, where they were held prisoner; Llywelyn ap Dafydd died there in 1287, four years after his capture, and was buried in the Dominican Church. Owain ap Dafydd survived his brother. The date of his death is unknown, but it was after 1305, when the King of England ordered a cage made of timber, bound with iron, in which to hold Owain ap Dafydd more securely at night. Edward I took the title of "Prince of Wales" for the Crown, bestowing it upon his son, Edward, at a Parliament held in Lincoln in 1301 at the age of seventeen. The title is still given to the heir apparent to the British crown to this day. Nicki Bullinga wrote a historical novel, "Gwenllian. The Lost Princess", published by The Simon the Montfort Society (2017).