The legal system on the Isle of Man is Manx customary law, a form of common law. Manx law originally derived from Gaelic Brehon law and Norse Udal law. Since those early beginnings, Manx law has developed under the heavy influence of English common law, and the uniqueness of the Brehon and Udal foundation is now most apparent only in property and constitutional areas of law. Precedent Manx law has a distinct system of insular binding precedent based on cases brought before the Island's courts. Precedents in the English legal system, when relevant and applicable, are persuasive upon the Manx courts. The supreme court for the Isle of Man is the Judicial Committee of the Privy Council. The Isle's traditional local appellate court is the Staff of Government Division. Statute In addition to precedent, the laws of the Island develop through statute from two main sources: Acts of Tynwald (known as insular legislation) and Acts of Parliament in Westminster. The power of the United Kingdom Parliament, and its predecessor the English Parliament, to legislate directly for the Isle of Man has a long history, and significantly pre-dates the 1765 revestment of the Island to the British Crown. One such example of English legislation applied to Man was the Bishoprics of Chester and Man Act 1541, which attached the Diocese of Sodor and Man to the Province of York. The judgement in the Derby Dower Case (1523) clarified the extension of English statutes to the Isle of Man, stating that a reference to the Island was required: "no general Act of Parliament extended to the island, but that by special name an Act might extend to it". The apparent requirement for an explicit reference to the Isle of Man within an Act of Parliament was rejected by the Staff of Government Division in Attorney-General v Harris & Mylrea (1894) wherein they ruled that the clear intention of Parliament to extend an Act to the Island was sufficient. Therefore, English (and, later, UK) legislation does not by default extend to the Isle of Man. In most cases it will be specifically applied to the Island (today done by the use of an Order in Council), and this is customarily done with the consent and approval of Tynwald. It has been held by the Judicial Committee of the Privy Council (on 5 August 1663 in William Christian's case) that Acts of Parliament can