Northern Ireland law
Northern Ireland law refers to the legal system of statute and common law operating in Northern Ireland since the partition of Ireland established Northern Ireland as a separate jurisdiction within the United Kingdom in 1921.
For the purposes of private international law the United Kingdom is divided into three distinct legal jurisdictions:Northern Ireland is a common law jurisdiction. Although its common law is similar to that in England and Wales, and partially derives from the same sources, there are some important differences in law and procedure between Northern Ireland and England and Wales. While influenced by English law, the Northern Ireland legal system is distinctive for a number of reasons: it has roots in Irish common law prior to Irish independence in 1921; following Irish independence, Northern Ireland became a devolved jurisdiction within the United Kingdom.
Ulster
In early medieval Ireland, a branch of the Northern Uí Néill, the Cenél nEógain of the province of Ailech, gradually eroded the territory of the province of Ulaidh until it lay east of the River Bann. The Cenél nEógain would make Tír Eóghain (most of which forms modern County Tyrone) their base. Among the High Kings of Ireland were Áed Findliath (died 879), Niall Glúndub (died 919), and Domnall ua Néill (died 980), all of the Cenél nEógain. The province of Ulaidh would survive restricted to the east of modern Ulster until the Norman invasion in the late 12th century. It would only once more become a province of Ireland in the mid-14th century after the collapse of the Norman Earldom of Ulster, when the O'Neills who had come to dominate the Northern Uí Néill stepped into the power vacuum and staked a claim for the first time the title of "king of Ulster" along with the Red Hand of Ulster symbol. It was then that the provinces of Ailech, Airgialla, and Ulaidh would all merge largely into what would become the modern province of Ulster.
Domnall Ua Lochlainn (died 1121) and Muirchertach Mac Lochlainn (died 1166) were of this dynasty. The Meic Lochlainn were in 1241 overthrown by their kin, the clan Ó Néill (see O'Neill dynasty). The Ó Néill's were from then on established as Ulster's most powerful Gaelic family.