Question: Ælfwine of Deira is the brother of a King of Northumbria that died in what year?

Context paragraphs:
Ælfwine Haroldsson: Ælfwine Haroldsson or Ælfwine was most probably an illegitimate son of King Harold Harefoot of England.  He was probably born during the early 1030s, either in Scandinavia or after 1035 in England.  He appears in an early twelfth-century cartulary from the monastery of Sainte Foi at Conques in Aquitaine as "Alboynus" (a cognate of Ælfwine), alongside the records that he was born in London and was the son of a King "Heroldus" (a Latinised version of Harold) and one "Alveva" ("Ælfgifu" Latinised).  It is also noted that he arrived in Conques in 1060 on pilgrimage and persuaded the local authorities to rebuild the church and make him prior.  W. H. Stevenson showed the only chronologically plausible candidate for his father is King Harold Harefoot.  With Harold Harefoot's sudden death on 17 March 1040 Ælfwine was most likely left in his otherwise unknown mother's care, or even that of his powerful and influential grandmother Ælfgifu of Northampton, who may be the Ælfgifu of the record mistakenly named as his mother, rather than grandmother.  He did not lay any claim to the throne of England.  Little is known about him, but he is thought to have died in the 1070s or 1080s.  He was a grandson of Cnut the Great.

Cadwallon ap Cadfan: Cadwallon ap Cadfan (died 634) was the King of Gwynedd from around 625 until his death in battle.  The son and successor of Cadfan ap Iago, he is best remembered as the King of the Britons who invaded and conquered the Kingdom of Northumbria, defeating and killing its king, Edwin, prior to his own death in battle against Oswald of Bernicia.  His conquest of Northumbria, which he held for a year or two after Edwin died, made him the last Briton to hold substantial territory in eastern Britain until the rise of the House of Tudor.  He was thereafter remembered as a national hero by the Britons and as a tyrant by the Anglo-Saxons of Northumbria.

Osric of Northumbria: Osric was king of Northumbria from the death of Coenred in 718 until his death on 9 May 729.  Symeon of Durham calls him a son of Aldfrith of Northumbria, which would make him a brother, or perhaps a half-brother, of Osred.  Alternatively, he may have been a son of King Eahlfrith of Deira, and thus a first cousin of Osred.

Ecgfrith of Northumbria: Ecgfrith (c. 645 – 20 May 685) was the King of Deira from 664 until 670, and then King of Northumbria from 670 until his death in 685.  He ruled over Northumbria when it was at the height of its power, but his reign ended with a disastrous defeat at the Battle of Nechtansmere in which he lost his life.

Ælfwine of Deira: Ælfwine (c. 661–679) was the King of Deira from 670 to 679.  He was a son of Oswiu of Northumbria and a brother of Ecgfrith of Northumbria.

Ælla of Deira: Ælla (Ella, Ille) (died 588), is the first certain king of Deira.  One of his sons was Edwin of Northumbria and his daughter Acha married Æthelfrith of Bernicia.

Æthelfrith: Æthelfrith (died c. 616) was King of Bernicia from c. 593 until his death.  Around 604 he became the first Bernician king to also rule the neighboring land of Deira, giving him an important place in the development of the later kingdom of Northumbria.  He was especially notable for his successes against the Britons and his victory over the Gaels of Dál Riata.  Although he was defeated and killed in battle and replaced by a dynastic rival, his line was eventually restored to power in the 630s.

Oswiu: Oswiu, also known as Oswy or Oswig (Old English: "Ōswīg" ) (c. 612 – 15 February 670), was King of Bernicia from 642 until his death.  One of the sons of Æthelfrith of Bernicia, he became king following the death of his brother Oswald in 642.  Unlike Oswald, Oswiu struggled to exert authority over Deira, the other constituent kingdom of medieval Northumbria, for much of his reign.

List of monarchs of Northumbria: Northumbria, a kingdom of Angles, in what is now northern England and south-east Scotland, was initially divided into two kingdoms: Bernicia and Deira.  The two were first united by Aethelfrith around the year 604, and except for occasional periods of division over the subsequent century, they remained so.  The exceptions are during the brief period from 633 to 634, when Northumbria was plunged into chaos by the death of King Edwin in battle and the ruinous invasion of Cadwallon ap Cadfan of Gwynedd.  The unity of the Northumbrian kingdoms was restored after Cadwallon's death in battle in 634.

Osric of Deira: Osric (died 633 or 634) was a King of Deira (632–633 or 633–634) in northern England.  He was a cousin of king Edwin of Northumbria, being the son of Edwin's uncle Æthelric of Deira.  Osric was also the father of Oswine.

Supporting paragraphs: Ælfwine of Deira Ecgfrith of Northumbria
Answer: 685