English law
Common law is a term with historical origins in the legal system of England. It denotes, in the first place, the judge-made law that developed from the early Middle Ages as described in a work published at the end of the 19th century, "The History of English Law before the Time of Edward I", in which Pollock and Maitland expanded the work of Coke (17th century) and Blackstone (18th century). Specifically, the law developed in England's Court of Common Pleas and other common law courts, which became also the law of the colonies settled initially under the crown of England or, later, of the United Kingdom, in North America and elsewhere; and this law as further developed after those courts in England were reorganised by the Supreme Court of Judicature Acts passed in the 1870s, and developed independently, in the legal systems of the United States and other jurisdictions, after their independence from the United Kingdom, before and after the 1870s. The term is used, in the second place, to denote the law developed by those courts, in the same periods (pre-colonial, colonial and post-colonial), as distinct from within the jurisdiction, or former jurisdiction, of other courts in England: the Court of Chancery, the ecclesiastical courts, and the Admiralty court.
Law
Equity is a body of rules that developed in England separately from the "common law". The common law was administered by judges and barristers. The Lord Chancellor on the other hand, as the King's keeper of conscience, could overrule the judge-made law if he thought it equitable to do so. This meant equity came to operate more through principles than rigid rules. For instance, whereas neither the common law nor civil law systems allow people to split the ownership from the control of one piece of property, equity allows this through an arrangement known as a 'trust'. 'Trustees' control property, whereas the 'beneficial' (or 'equitable') ownership of trust property is held by people known as 'beneficiaries'. Trustees owe duties to their beneficiaries to take good care of the entrusted property. In the early case of "Keech v Sandford" [1722] a child had inherited the lease on a market in Romford, London. Mr Sandford was entrusted to look after this property until the child matured. But before then, the lease expired. The landlord had (apparently) told Mr Sandford that he did not want the child to have the renewed lease. Yet the landlord was happy (apparently) to give Mr Sandford the opportunity of the lease instead. Mr Sandford took it. When the child (now Mr Keech) grew up, he sued Mr Sandford for the profit that he had been making by getting the market's lease. Mr Sandford was meant to be trusted, but he put himself in a position of conflict of interest. The Lord Chancellor, Lord King, agreed and ordered Mr Sandford should disgorge his profits. He wrote,