Llywelyn was killed on 11 December 1282.  The circumstances of his death are disputed (see link below).  About six months later the whole of Wales came under English control.  Little Gwenllian was Llywelyn's heir, and Edward I, King of England, did not want her to have children who might rebel against him, so at the age of one she was taken to the convent at Sempringham in Lincolnshire.  She spent the rest of her life there.  She died there on 7 June 1337 aged 54.

For more information about the historical background to Gwenllian, click here.