Eleanor (Elinor in Welsh) de Montfort (1252-1282) was the wife of Llywelyn ap Gruffydd, the last Prince of Wales. She was the daughter of Simon de Montfort, who was killed in the Battle of Evesham by the forces of Edward I when she was only thirteen. Her mother, Eleanor of Leicester, was the youngest daughter of King John of England and his wife, Isabella of Angouleme. Interestingly, that made Elinor’s mother and Joanna, Princess of Wales and the wife of Llywelyn Fawr (Llywelyn ap Gruffydd’s grandfather), half-sisters. Joanna had been born in 1191. After Simon de Montfort’s death, Elinor and her mother) found refuge at the Dominican nunnery of Monargis in France. http://en.wikipedia.org/wiki/Joan,_Lady_of_Wales
J. Beverely Smith writes: “Llywelyn’s decision to marry Simon de Montfort’s daughter was revealed in dramatic circumstances at the end of 1275. Eleanor was travelling from France to join the prince [whom she had already married per verba de presenti–or inabsentia] when she was detained at sea and taken into Edward’s custody. She sailed in the company of her brother Amaury, and the king was jubilant at a capture which placed Montfort’s son and daughter in his hands and revealed, hidden beneath the ship’s boards, the arms and banner of the Montforts” (1998:390). Finally, by Edward’s lights, he had real justification for re-entering Wales and forcing Llywelyn to submit to England once and for all. Note that Elinor was also Edward’s cousin.
For Llywelyn’s part, he had decided to marry Elinor after the events of 1274 when his brother, Dafydd, and other conspirators had tried to kill him. Nobody knows why he’d waited this long to marry (he was now approaching 50 years old) but his failure to father a child with any woman up until then might have played a role–once married, there was no chance to father a child with another woman who might prove more fertile, AND have that child acknowledged by Edward and/or the Church.
In the end, Edward kept Elinor captive for three years, until after Llywelyn had lost the war of 1277 and submitted to Edward at Rhuddlan castle. Elinor and Llywelyn were married (again) on October 13th (the Feast of St. Edward) in 1278, at the cathedral church at Worcester. Edward gave Elinor away.
Wales remained at peace until 1282, when Prince Dafydd’s men launched a surprise attack on English castles on Palm Sunday. Elinor herself died in childbirth on June 19, 1282 at Garth Celyn, and was buried across the Menai Strait at Llanfair Abbey, beside her aunt, Joanna. No trace remains of her grave.
From The Chronicles of the Princes (Red Book of Hergest): “And then, on the Feast of St. Edward, the marriage of Llywelyn and Eleanor solemnized at Winchester, Edward, king of England himself bearing the cost of the banquet and nuptial on the feast of St. festivities liberally. And of that Eleanor there was a daughter to Llywelyn, called Gwenllian and Eleanor died in childbirth, and was buried in the chapter house of the barefooted friars at Llanvaes in Mona. Gwenllian, after the death of her father, was taken as a prisoner to England, and before she was of age, she was made a nun against her consent.”