High Quality Content by WIKIPEDIA articles! 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.