Æthelstan Ætheling (Old English: Æþelstan Æþeling; early or mid 980s – 25 June 1014) was the eldest son of King Æthelred the Unready by his first wife Ælfgifu, and was the heir apparent to the kingdom until his death. He is first mentioned as a witness to a charter of his father in 993. He probably spent part of his childhood at Æthelingadene, Dean in west Sussex, and his paternal grandmother Ælfthryth may have played an important part in his upbringing. Almost nothing is known of his life, although he seems to have formed a friendship with Sigeforth and Morcar, two of the leading thegns of the Five Boroughs of the East Midlands.
In December 1013 the Danish king Sweyn conquered England and King Æthelred was forced into exile in Normandy, but he returned following Sweyn's death in February 1014. It is not known what became of Æthelstan and his surviving full brothers, Edmund Ironside and Eadwig, during Sweyn's rule, but they probably remained somewhere in England. Æthelstan's last mention in a charter is in one dated 1013.
