Scandinavian York in the context of "Alfred the Great"

The Kingdom of England was a sovereign state on the island of Great Britain from the 10th century, when it was unified from various Anglo-Saxon kingdoms, until 1 May 1707, when it united with Scotland to form the Kingdom of Great Britain, which would later become the United Kingdom. The Kingdom of England was among the most powerful states in Europe during the medieval and early modern periods.

Beginning in the year 886 Alfred the Great reoccupied London from the Danish Vikings and after this event he declared himself King of the Anglo-Saxons, until his death in 899. During the early tenth century, the various Anglo-Saxon kingdoms were united by Alfred's descendants Edward the Elder (reigned 899–924) and Æthelstan (reigned 924–939) to form the Kingdom of the English. In 927, Æthelstan conquered the last remaining Viking kingdom, York, making him the first Anglo-Saxon ruler of the whole of England. In 1016, the kingdom became part of the North Sea Empire of Cnut the Great, a personal union between England, Denmark and Norway. The Norman Conquest in 1066 led to the transfer of the English capital city and chief royal residence from the Anglo-Saxon one at Winchester to Westminster, and the City of London quickly established itself as England's largest and principal commercial centre.

The Viking Age (about 793–1066 CE) was the period during the Middle Ages when Norsemen known as Vikings undertook large-scale raiding, colonising, conquest, and trading throughout Europe and reached North America. The Viking Age applies not only to their homeland of Scandinavia but also to any place significantly settled by Scandinavians during the period. Although few of the Scandinavians of the Viking Age were Vikings in the sense of being engaged in piracy, they are often referred to as Vikings as well as Norsemen.

Voyaging by sea from their homelands in Denmark, Norway, and Sweden, the Norse people settled in the British Isles, Ireland, the Faroe Islands, Iceland, Greenland, Normandy, and the Baltic coast and along the Dnieper and Volga trade routes in eastern Europe, where they were also known as Varangians. They also briefly settled in Newfoundland, becoming the first Europeans to reach North America. The Norse-Gaels, Normans, Rus' people, Faroese, and Icelanders emerged from these Norse colonies. The Vikings founded several kingdoms and earldoms in Europe: the Kingdom of the Isles (Suðreyjar), Orkney (Norðreyjar), York (Jórvík) and the Danelaw (Danalǫg), Dublin (Dyflin), Normandy, and Kievan Rus' (Garðaríki). The Norse homelands were also unified into larger kingdoms during the Viking Age, and the short-lived North Sea Empire included large swathes of Scandinavia and Britain. In 1021, the Vikings achieved the feat of reaching North America—the date of which was not determined until a millennium later.

Æthelstan or Athelstan (/ˈæθəlstæn/; Old English: Æðelstān [ˈæðelstɑːn]; Old Norse: Aðalsteinn; lit. 'noble stone'; c. 894 – 27 October 939) was King of the Anglo-Saxons from 924 to 927 and King of the English from 927 to his death in 939. He was the son of King Edward the Elder and his first wife, Ecgwynn. Modern historians regard him as the first King of England and one of the "greatest Anglo-Saxon kings". He never married and had no children; he was succeeded by his half-brother, Edmund I.

When Edward died in July 924, Æthelstan was accepted by the Mercians as king. His half-brother Ælfweard may have been recognised as king in Wessex, but died within three weeks of their father's death. Æthelstan encountered resistance in Wessex for several months, and was not crowned until September 925. In 927, he conquered the last remaining Viking kingdom, York, making him the first Anglo-Saxon ruler of the whole of England. In 934, he invaded Scotland and forced Constantine II to submit to him. Æthelstan's rule was resented by the Scots and Vikings, and in 937 they invaded England. Æthelstan defeated them at the Battle of Brunanburh, a victory that gave him great prestige both in the British Isles and on the Continent. After his death in 939, the Vikings seized back control of York, and it was not finally reconquered until 954.

Jorvik Viking Centre is a museum and visitor attraction in York, England, containing lifelike mannequins and life-size dioramas depicting Viking life in the city. Visitors are taken through the dioramas in 'time capsule' carriages equipped with speakers. It was created by York Archaeological Trust and opened in 1984. Its name is derived from Jórvík, the Old Norse name for York and the surrounding Viking Kingdom of Yorkshire.

The Kingdom of the East Angles, informally known as the Kingdom of East Anglia, was a small independent kingdom of the Angles during the Anglo-Saxon period comprising what are now the English counties of Norfolk and Suffolk and perhaps the eastern part of the Fens; the area still known as East Anglia.

The kingdom formed in the 6th century in the wake of the Anglo-Saxon settlement of Britain and was one of the kingdoms of the Heptarchy. It was ruled by the Wuffingas dynasty in the 7th and 8th centuries, but the territory was taken by Offa of Mercia in 794. Mercian control lapsed briefly following the death of Offa but was reestablished. The Danish Great Heathen Army landed in East Anglia in 865; after taking York it returned to East Anglia, killing King Edmund ("the Martyr") and making it Danish land in 869. After Alfred the Great forced a treaty with the Danes, East Anglia was left as part of the Danelaw.

Edmund I or Eadmund I (920/921 – 26 May 946) was King of the English from 27 October 939 until his death in 946. He was the elder son of King Edward the Elder and his third wife, Queen Eadgifu, and a grandson of King Alfred the Great. After Edward died in 924, he was succeeded by his eldest son, Edmund's half-brother Æthelstan. Edmund was crowned after Æthelstan died childless in 939. He had two sons, Eadwig and Edgar, by his first wife Ælfgifu, and none by his second wife Æthelflæd. His sons were young children when he was killed in a brawl with an outlaw at Pucklechurch in Gloucestershire, and he was succeeded by his younger brother Eadred, who died in 955 and was followed by Edmund's sons in succession.

Æthelstan had succeeded as the king of England south of the Humber and he became the first king of all England when he conquered Viking-ruled York in 927, but after his death Anlaf Guthfrithson was accepted as King of York and extended Viking rule to the Five Boroughs of north-east Mercia. Edmund was initially forced to accept the reverse, the first major setback for the West Saxon dynasty since Alfred's reign, but he was able to recover his position following Anlaf's death in 941. In 942, Edmund took back control of the Five Boroughs and in 944 he regained control over the whole of England when he expelled the Viking kings of York. Eadred had to deal with further revolts when he became king, and York was not finally conquered until 954. Æthelstan had achieved a dominant position over other British kings and Edmund maintained this, perhaps apart from Scotland. The north Welsh king Idwal Foel may have allied with the Vikings as he was killed by the English in 942. The British kingdom of Strathclyde may also have sided with the Vikings as Edmund ravaged it in 945 and then ceded it to Malcolm I of Scotland. Edmund also continued his brother's friendly relations with Continental rulers, several of whom were married to his half-sisters.