[1] He fought in the revolt of Owain Glyndŵr, and then lived as a rebel outlaw.
[2] However, after the failure of Glyndŵr's rebellion, Llywelyn appears to have changed his allegiance; Sir William ap Thomas is later attested as his patron.
[1] Later in his life, Llywelyn became religious, and was ultimately buried at Strata Marcella.
[3] In his early career, Llywelyn studied under a poet named Rhys ap Dafydd ab Iorwerth.
[3] Llywelyn is noted for his bardic debate between himself and Rhys Goch Eryri on the nature and origin of the poetic muse, or awen.