The British Isles are a crossroads for both the mortal and supernatural worlds. Their long history of invasion and integration has led to the presence of many different groups of people and conflicts between stretching far back into history.
Note on terminology: The term "British Isles" refers collectively to the major islands of Great Britain and Ireland, plus smaller adjacent islands such as the Isle of Man. The "United Kingdom" refers to the countries of England, Wales, Scotland, and Northern Ireland. "Great Britain" refers to the island that encompasses England, Scotland and Wales. "Britain" can, depending on context, refer to Great Britain or to the UK. "Ireland" can refer to the island of Ireland itself or to either of the two countries located there: the Republic of Ireland, which is an independent nation, and Northern Ireland, which is part of the UK.
The history of Kindred in the British Isles is dominated, both politically and psychologically, by the Baronies of Avalon. These domains were separated into fiefs in the Dark Medieval, ruled over by the Fief of London which was, even then, the domain of the fabled Mithras. While Mithras's rule of the island of Britain was never overturned, it was challenged by the Scottish Toreador lords and the Tremere of England. The Cainites of Wales and Ireland were likewise controlled by politics in London as much as they disliked it and refused loyalty to Mithras. The powerful Prince had influence throughout the British Isles and even though he collected no tribute from some of the farther reaches, all of the islands responded to his machinations in the Dark Medieval.
Mithras's rule continued through the 19th and 20th centuries with the rest of the British Isles becoming more or less independent as the vagaries of mortal and Kindred politics dictated. As the British Empire spread throughout the world, the influence of the United Kingdoms' Kindred spread as well and Mithras consolidated his power. He became well respected throughout the world, but a Tremere resurgence in the 1920s caused infighting among the Kindred of London.
During World War II, when much of London was bombed to rubble, Mithras mysteriously disappeared. His absence has set the stage for power grabs throughout the British Isles notably the Anarch Movement, which is only growing stronger.
The mages of the British Isles during the Dark Ages were fractured and conflicted, within and between the Fellowships. The Order of Hermes was active in England, pursuing its Massasa War with the Tremere vampires, and held particularly influential chantries in London, Winchester, and Oxford. They also had a scattered presence in the Scottish highlands and the Channel Islands, though these chantries were well-hidden to avoid conflict with the other Fellowships, as well as other supernatural creatures. The Messianic Voices had many powerful chantries in England including the cities London, Winchester, Norwich, Glastonbury (rumored to be the resting place of the Holy Grail among other relics), Canterbury, and Oxford. In the rest of the Isles the Voices were internally segregated between those who followed the older Celtic Christianity and those who were loyal to Rome. St. Patrick's Cathedral in Dublin is the central Messianic authority in Ireland and the Appey of Holyrood in Edinburgh is its counterpart in Scotland. Bardsey in Wales is a beacon of power for the Voices, while nearby Powys holds a struggle between that Fellowship and the Old Faith. The Old Faith and the Spirit-Talkers were marginalized in the Dark Medieval by the march of Christianity and so remained strong only in the Scottish highlands, the wilds of northern and western Ireland and the mountainous terrain of Wales. These were large portions of the Isles, but they lacked significant populations and the two Fellowships regularly struggled to maintain their territory against the more Christian mages.
From all the wars which have swept the British Isles the Restless Dead have always been present in the islands. Travelers through Scotland reported ghosts haunting the countryside, connected somehow with the Dunsirn branch of the Giovanni clan of vampires.
- 4000 BCE - 2800 BCE: Thanatoic and Ecstatic cults arise in India. The Akashic Brotherhood takes form in China and Tibet. Babylonian priest-scientists discover principles of geometry and astronomy, harnessing the power of mathematics and the heavens to the human will. Druidic priests and practitioners of magic raise Stonehenge in accordance with the movements of celestial bodies. Although Stonehenge serves as a Cray, it is not itself a Cray. Rather it was erected by the Wyck as a "lens" over a natural upwelling of wild magick.
- 1200 BCE: Around this time, fomori appear. Fianna battle in the Fomorian Wars for the British Isles.
- 43 CE-410 CE: Period of Roman Britain. Fianna discover "Hollow Men" fomori there at this time. 
- 1192: The Toreador allegedly manipulate Pope Celestine III into separating the Scottish Church from the Ventrue-controlled Archdiocese of York.
- 1198: The English river Exe is dammed, preventing all passage by ship to the (former) port city of Exeter.