The common law is a non-codified form of law based on long-accepted customs and traditions. The term is used to define the scope of the right to a jury trial as guaranteed by the Seventh Amendment to the U.S. Constitution, which some consider to be the most important part of the Bill of Rights.
Common law developed in England over many centuries, beginning with the reign of Henry II in the 12th century and continued in former and current British territories and colonies. Common law was also the product of the Anglo-Saxons, Jews, Vikings, and Romans. It was referred to as the common law because it was (and remains) common to all of England. The United States (except for Louisiana) and the United Kingdom are two prominent countries that have a common law legal system. The ICJ also uses common law.
“[T]he rules of the common law of England were adopted as the principles which were to direct the proceedings of the provincial government, whether legislative or judicial.” Baltimore Sun Co. v. Mayor & City Council of Baltimore, 359 Md. 653, 661, 755 A.2d 1130, 1134 (Md. 2000).
"Common law" is used to denote three distinct concepts:
1. Common law as opposed to statutory law. That is, the law of precedent as opposed to the law expressed in legislation. In the common law countries judges will apply the common law in the absence of a statute governing a particular matter in issue.
2. Common law as opposed to Civil Law. That is, the common law legal system as opposed to the legal system adopted by most of continental Europe.
3. Common law as opposed to equity. That is, the law that applied in the former common law courts as opposed to that which applied in the former Court of Chancery. In England, the Judicature Act of 1873 created a new system which gave the courts both legal (common law) and equitable jurisdiction.
The strict definition of common law ("3" above) is best characterized by the theories, principles, and rules of law exhibited in litigation making use of the old English common law forms of action. In modern civil procedure, actions at law are brought by making filings creating a civil action "in the nature of" one or more of the common law forms of action. These common law actions include:
1. The diverse Real Actions of the Old Common Law.
2. Ejectment. The more modern consolidated real action. For Recovery of possession of realty.
3. Debt. Recovery of debts fixed or ascertainable in amount, under seal, or contracted for such as by purchase of goods and services on credit.
4. Covenant. For breach of certain express written contractual obligations where the values involved are in dispute and must be proven and found at trial.
5. Detinue. Recovery of personal property after trial, or amount of damages.
6. Replevin. A form of action where personal property may be recovered pre-trial if plaintiff assumes risk of losing trial by making a legal bond in favor of the defendant if the defendant should win at trial. Detinue and Replevin are good examples showing the constitutional requirements for pre-trial attachments of assets in general.
7. Trover. Recovery of damages for lost or converted personal property.
8. Trespass on the Case. Recovery of damages for diverse tort injuries.
9. Assumpsit. Recovery of debts, especially debts arising under theories that may imply the creation of a debt without expression or without privity of contract, such as theories of subrogation, quasi-contract, novation, assignment, and assumption.
Relationship to Islamic law
It has recently been pointed out that certain features of English Common Law bear a striking resemblance to Islamic law of the High Middle Ages, in particular to the Maliki School of Jurisprudence. In particular, concepts such as trial by jury, land possession, and perpetual endowment have no affinity with either Roman Law, which was becoming established in western Europe at the time, or with Anglo-Saxon local customary laws which preceded English Common Law, but have exact parallels in the Maliki legal system (e.g. the concept of a perpetual endowment in ECL is essentially identical to that of a waqf in Islamic jurisprudence).
A potential source of Islamic legal ideas was the court of Sicily, where the Norman rulers retained many customs and laws from the previous Muslim rulers, whose legal advisers were of the Maliki School. It has been noted that Thomas Brown, an English civil servant, worked in the Sicilian Court in the 12th century and later joined the court of Henry II of England at the very time that the Common Law was being established. Brown (known as Qaid Brun in Sicily), brought mathematical ideas from Sicily to England (e.g. the Arabic/Hindu numerals) and could equally have brought legal ideas as well, although there is no direct evidence that he did so.
One distinct difference between common law and Sharia Law is that common law does not call for the gruesome murder of individuals for non-compliance with Muslim traditions.