Udal law is a Norse-derived legal system, found in Shetland and Orkney in Scotland, and in Manx law in the Isle of Man. It is closely related to Odelsrett; both terms are from Proto-Germanic *Ōþalan, meaning "heritage; inheritance". History Udal law was codified by the Norwegian kings Magnus I and Magnus VI. The Treaty of Perth transferred the Outer Hebrides and Isle of Man to Scots law, while Norse law and rule still applied for Shetland and Orkney. The courts of Scotland have intermittently acknowledged the supremacy of udal law in property cases up to the present day. Major differences from Scots law include shore ownership rights, important for pipelines and buried cables. Udal law generally holds sway in Shetland and Orkney, along with Scots law. Description Not all land in Shetland and Orkney can be described as falling under udal tenure. The type of tenure depends on how the title arose: Unwritten udal title, while rare, does exist, for udal law did not require written title deeds. Recorded udal titles, as entered in the Sasine Register, provides proof by prescription for the purposes of the Prescription and Limitation (Scotland) Act 1973. Some udal proprietors resigned their lands to the Crown in exchange for a grant of feudal title to the dominium utile, thus removing the land from udal law. Where some feu dispositions arose in quasi-feudal circumstances, such as sales under the right to buy legislation with respect to council houses, the terms of the relevant deed will govern which tenure applies. The udal tenant held without charter by uninterrupted possession on payment to the Crown, the kirk, or a grantee from the Crown of a tribute called skat (), now meaning "tax"; cognate with the English term scot, which referred to a similar payment), or without such payment, the latter right being more strictly the udal right. They were convertible into feus at the option of the udallers. Succession law had unique traits, as the eldest son inherited the father's main residence, while the rest of the property was shared among siblings, daughters inheriting half as much as sons. Several significant aspects of udal law are not seen elsewhere in the UK: While in the rest of Britain ownership of land extends only to the high water mark (where the Crown is deemed to own what lies below it), in Orkney and Shetland it extends to the lowest