Deira in the context of "York"

Y Gododdin (Welsh: [əː ɡɔˈdɔðɪn]) is a medieval Welsh poem consisting of a series of elegies to the men of the Brittonic kingdom of Gododdin and its allies who, according to the conventional interpretation, died fighting the Angles of Deira and Bernicia at a place named Catraeth in about AD 600. It is traditionally ascribed to the bard Aneirin and survives only in one manuscript, the "Book of Aneirin".

The Book of Aneirin manuscript is from the later 13th century, but Y Gododdin has been dated to between the 7th and the early 11th centuries. The text is partly written in Middle Welsh orthography and partly in Old Welsh. The early date would place its oral composition soon after the battle, presumably in the Hen Ogledd ("Old North"); as such it would have originated in the Cumbric dialect of Common Brittonic. Others consider it the work of a poet from Wales in the 9th, 10th, or 11th century. Even a 9th-century date would make it one of the oldest surviving Welsh works of poetry.

Northumbria (/nɔːrˈθʌmbriə/) was an early medieval kingdom in what is now Northern England and South Scotland.

The name derives from the Old English Norþanhymbre meaning "the people or province north of the Humber", as opposed to the people south of the Humber Estuary. What was to become Northumbria started as two kingdoms, Deira in the south and Bernicia in the north. Conflict in the first half of the seventh century ended with the murder of the last king of Deira in 651, and Northumbria was thereafter unified under Bernician kings.

The Old North (Welsh: Hen Ogledd, Welsh pronunciation: [ˌheːn ˈɔɡlɛð]) is the term used in modern scholarship for the historical and literary space which was inhabited by Brittonic-speaking peoples of modern Northern England and southern Scotland in the Early Middle Ages. The people of Wales and those of the Old North considered themselves to be one people, and both were referred to as Cymry ('fellow-countrymen') from the Brittonic word combrogi. The Old North was distinct from the parts of Great Britain inhabited by the Picts, Anglo-Saxons, and Scoti.

The major kingdoms of the Old North were Elmet, Gododdin, Rheged, and the Kingdom of Strathclyde (Welsh: Ystrad Clud). Smaller kingdoms included Aeron and Calchfynydd. Eidyn, Lleuddiniawn, and Manaw Gododdin were evidently parts of Gododdin. The later Anglian kingdoms of Deira and Bernicia both had Brittonic-derived names, suggesting they may have been Brittonic kingdoms originally. All the kingdoms of the Old North except Strathclyde were gradually either integrated or subsumed by the emerging Anglo-Saxon kingdoms, Gaelic Scots and fellow Brittonic Picts by about 800; Strathclyde was eventually incorporated into the rising Middle Irish-speaking Kingdom of Scotland in the 11th century.

Edwin (Old English: Ēadwine; c. 586 – 12 October 632/633), also known as Eadwine or Æduinus, was the King of Deira and Bernicia – which later became known as Northumbria – from around 616 until his death. He was the second monarch to rule both of these northern English kingdoms and the first to convert to Christianity. After he died in battle, he was venerated as a saint.

Edwin was the son of Ælle, the first known king of Deira, and likely had at least two siblings. His sister Acha was married to Æthelfrith, king of neighbouring Bernicia. Edwin was forced into exile when Æthelfrith conquered Deira. His travels took him to the court of Rædwald of East Anglia, who defeated Æthelfrith in 616, allowing Edwin to ascend the thrones of Bernicia and Deira. After the death of his patron Rædwald around 624, Edwin became the most powerful ruler in Britain. Bede the Venerable includes him in his list of kings who exercised imperium over other Anglo-Saxon monarchs, and the Anglo-Saxon Chronicle gives him the title bretwalda, or "ruler of Britain".

Bernicia (Old English: Bernice, Beornice) was an Anglo-Saxon kingdom established by Anglian settlers of the 6th century in what is now southeastern Scotland and North East England.

The Anglian territory of Bernicia was approximately equivalent to the modern English counties of Northumberland, Tyne and Wear, and Durham, as well as the Scottish counties of Berwickshire and East Lothian, stretching from the Forth to the Tees. In the early 7th century, it merged with its southern neighbour, Deira, to form the kingdom of Northumbria, and its borders subsequently expanded considerably.

The Battle of Catraeth was a legendary battle fought around AD 600 between a force raised by the Gododdin, a Brythonic people of the Hen Ogledd or "Old North" of Britain, and the Angles of Bernicia and Deira. It was evidently an assault by the Gododdin party on the Angle stronghold of Catraeth, perhaps Catterick, North Yorkshire. The Gododdin force was said to have consisted of warriors from all over the Hen Ogledd, and even some from as far afield as Gwynedd in North Wales and Pictland. The battle was disastrous for the Britons, who were nearly all killed. The slain warriors were commemorated in the important early poem Y Gododdin, attributed to Aneirin.

The Southumbrians (Old English: Sūþ(an)hymbre) were the Anglo-Saxon people occupying northern Mercia. The term might not have been used by the Mercians and was instead possibly coined by the Deiran or Bernician people as a territorial response to their own Kingdom of Northumbria. The Anglo-Saxon Chronicle refers to King Coenred as having become the King of the Southumbrians in 702, two years before he became King of all the Mercians. The fact that Coenred was the son of Wulfhere, the Mercian King, implies that Southumbria was a sub-kingdom of Mercia.

More generally, Southumbria is used by modern historians to refer conveniently to all of Anglo-Saxon England south of the Humber estuary not in Northumbria, especially in the period before England was unified.