Mansfield, William Murray, 1st earl of, 1705–93, English jurist. As solicitor general (1742–54) he prosecuted the Scottish rebel lords, Balmerino (Arthur Elphinstone), Kilmarnock, and Lovat. In 1756 he was raised to the peerage and made lord chief justice, a post he held until 1788. He rationalized many of the rules of procedure, reduced expense and delay, and tried to fuse the principles of law and equity. Though not fully successful in renovating the medieval law of property, he did establish a theory of contract that laid the foundation for modern commercial law. He attempted to apply continental analogies in order to bring English law closer to international practice. Mansfield was unpopular for his opinions on seditious libel and for his judgments in the case of John Wilkes, and his house was burned (1780) in the Gordon riots. His wide learning and forceful thinking greatly influenced Sir William Blackstone.