William Ætheling (Old English: ['wi?i?m 'æðeli?g]; 5 August 1103 – 25 November 1120), commonly called Adelin, sometimes Adelinus, Adelingus, A(u)delin or other Latinised Norman-French variants of Ætheling, was the son of Henry I of England by his wife Matilda of Scotland, and was thus heir apparent to the English throne.
His early death without issue caused a succession crisis, known in history as the Anarchy.