This book offers a fundamental reassessment of the origins of a central court in Scotland. It examines the early judicial role of Parliament, the development of the Session in the fifteenth century as a judicial sitting of the King’s Council, and its reconstitution as the College of Justice in 1532. Drawing on new archival research into jurisdictional change, litigation and dispute settlement, the book breaks with established interpretations and argues for the overriding significance of the foundation of the College of Justice as a supreme central court administering civil justice. This signalled a fundamental transformation in the medieval legal order of Scotland, reflecting a European pattern in which new courts of justice developed out of the jurisdiction of royal councils.