1. Professor of Legal History, University of Edinburgh. I am grateful to the Trustees of the National Library of Scotland, the Keeper of the Advocates' Library, the Keeper of the Records of Scotland, the Keeper of Muniments, University of St Andrews Library, the Archivist of the City of Edinburgh, and the Librarian and Archivist of the University of Edinburgh for permission to cite and quote from unpublished materials in their care. I am also grateful to Sir Robert Clerk of Penicuik and the Earl of Mar and...