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
Over decades and centuries, principles of law have been derived from customs. The divine right of kings, natural and legal rights, human rights, civil rights, and common law are early unwritten sources of law. Canon law and other forms of religious law form the basis for law derived from religious practices and doctrines or from sacred texts; this source of law is important where there is a state religion. Historical or judicial precedent and case law can modify or even create a source of law. Legislation, rules, and regulations are form the tangible source of laws which are codified and enforceable.