Common law
The common lawso named because it was "common" to all the king's courts across Englandoriginated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066. The British Empire spread the English legal system to its historical colonies, many of which retain the common law system today. These "common law systems" are legal systems that give great precedential weight to common law, and to the style of reasoning inherited from the English legal system.
Sources of law
Equity is a source of law peculiar to England and Wales. Equity is the case law developed by the (now defunct) Court of Chancery. Equity prevails over common law, but its application is discretionary. Equity's main achievements are: trusts, charities, probate, & equitable remedies. There are a number of equitable maxims, such as: “He who comes to equity must come with clean hands”.