"Dydd Santes Dwynwen"
Translation:Saint Dwynwen's day
Dewi Sant is a historical figure of some importance in Welsh history, so he is accorded a name equivalent to 'Dewi the Saint', rather like Hywel Dda (Hywel the Good), Owain Lawgoch (Owain Bloody-hand), Rhodri Mawr (Rhodri the Great) and many others. Similary, Richard Lionheart, Ethelred the Unrede, Alfred the Great, William the Bastard, and so on
Other saints such as Santes Dwynwen, Sant Celert, Sant Catwg, and so on were just common or garden saints of the early Welsh church.