Brut y Tywysogion aka Chronicle of the Princes of Wales. Edited by the Reverend John Williams ab Ithel, M.A. Rector of Llanymowddy, Merionethshire. 1860.

1230. One thousand two hundred and thirty was the year of Christ, when king Henry, having with him a vast armed host, sailed for France, with the intention of obtaining his right as to Normandy and Anjou and Poictou. And soon after that, on account of a storm and mortality, being disappointed of his purpose, he returned to England. That year, William Canton of Cemaes died. Then young Llywelyn, son of Maelgwn, died, on his estate in Gwynedd, and was honourably buried at Aberconway [Map].

1230. That year, William Bruse (age 26) was hanged by Llywelyn (age 58), son of Iorwerth, having been caught in the chamber of the prince, with the princess Jannet (age 39), daughter of king John, and wife of the prince.