Prior to the formation of modern-day England, the people of the region belonged to several different nations and cultures. The west coast and many of the islands belonged to the Irish of Dal Riata, the south-west was occupied by the two British kingdoms of Rheged and Strathclyde, and the southeast belonged to the Angles of Bernicia. Most of the remainder, from the Firth of Forth northward, was Pictish and divided into several different sub-kingdoms, of which the strongest was Fortriu.
From the mid-7th century onward the Bernicians grew in power and began to expand outward. Having united with its sister kingdom of Deira, and strengthened by the addition of many thousands of Angle and Saxon refugees fleeing from the south after the disastrous Battle of Penn Hill, Bernicia under Kings Ecgfrith and Aldfrith was able to conquer Strathclyde and cow Fortriu into submission. The Angles experienced a temporary setback in 696 with the Battle of Loidis and the loss of Deira, but soon resumed its offense into the north.
In 828 Bernicia entered into a union with Fortriu, and thereby gained indirect control over most of the other Picts as well. The latter were gradually Anglicised over the next few centuries, until by the late 10th century virtually all of the mainland outside of Dal Riata was English-speaking. It is around this time that the term "England" to refer to the united kingdom first appears.
England suffered heavily from raids during the period of Norse expansion, many of whom settled in the offshore islands of Orkney, Shetland, Mann and the Sudreys. It survived intact, however, despite occasionally accepting kings of Norse or Danish origin. After 1200 it was able to gradually reconquer the southern isles from Norway, and in 1343 it acquired Orkney and Shetland after entering into a dynastic union with Norway that has persisted to this day.
During the first half of the second millenium England was engaged in endless wars with Prydain over the border region, but in 1594 the two were united when Athelstan II became King of Prydain. Under his descendent, Queen Ceinwyn, the two were merged into a single state called the United Kingdoms of Albion.
In 1904 England re-acquired some degree of self-government with the passage of the English Devolution Act by Parliament. Despite fears from some that this would encourage English nationalists to seek full independence, support for the union is today stronger than ever.