 Scots law has a basis derived from Roman law, combining features of both uncodified civil law, dating back to the Corpus Juris Civilis, and common law with medieval sources. The terms of the Treaty of Union with England in 1707 guaranteed the continued existence of a separate legal system in Scotland from that of England and Wales. Prior to 1611, there were several regional law systems in Scotland, most notably Udal law in Orkney and Shetland, based on old Norse law. Various other systems derived from common Celtic or Brehon laws survived in the Highlands until the 1800s.
