Tywysog is Welsh for a ruling Prince or King. The work Brut y Tywysogion is the Annals of the Princes of Wales and is a historical narrative of the deeds of the various rulers of the petty kingdoms which existed in Wales from the end of Roman rule in Britain in c.410AD to the final conquest of Wales and the death of it's last consecrated native Tywysog Llywelyn ap Gruffydd of the Kingdom of Gwynedd in 1282. Another Tywysog was proclaimed in Owain Glyndwr, Lord of Glyndyfrdwy, and heir to Kingdom of Powys in 1400 but this too was extinguished by 1412.