Common law is a tradition of law originating in England in which courts develop legal rules through decisions in individual cases. It also denotes, more narrowly, judge-made rules distinguished from enacted legislation. Its characteristic method uses precedent: earlier decisions supply principles for resolving later disputes. As a legal tradition, common law includes statutory law and historically distinct equitable doctrines, rather than consisting exclusively of judicial decisions. (law.cornell.edu)
Meanings and scope
The expression has several related meanings. In comparative usage, it identifies a legal family contrasted with the civil-law tradition, which places greater emphasis on systematic codes. Within a particular jurisdiction, it may instead identify rules established by courts rather than a legislature. Historically, English lawyers also distinguished the common law administered by royal courts from equity, developed in the Court of Chancery. These meanings overlap but are not interchangeable: a statute remains part of a common-law legal system without itself being judge-made law. (justice.gc.ca)
“Unwritten law” is sometimes used for common law, but this does not mean that its rules are unrecorded. They are expressed in judicial decisions rather than collected exclusively in legislation. Likewise, “civil law” can mean either a legal tradition or noncriminal law; a civil dispute can therefore be governed by common-law principles. (justice.gc.ca)
Historical development
English common law developed during the Middle Ages through the expansion of royal justice. The reign of Henry II (1154–1189) was particularly important: royal judges travelled on circuits, while central courts acquired continuing institutional roles. Increasingly uniform royal justice provided a framework extending beyond separate local practices. Early juries also differed from modern juries, drawing substantially on local knowledge rather than solely on evidence presented at trial. (judiciary.uk)
The technical procedures of common-law courts could leave litigants without adequate relief. Petitions to the monarch were increasingly referred to the Lord Chancellor, whose Court of Chancery developed equity as a separate avenue of redress. Nineteenth-century judicial reforms brought the administration of common law and equity into a unified court structure. The Judicature Act 1873 established the basis for courts to administer both, with equitable rules prevailing in a conflict. Institutional unification did not make the historical distinction meaningless. (judiciary.uk)
Precedent and judicial reasoning
The doctrine of stare decisis—a Latin expression meaning “to stand by things decided”—organizes the authority of earlier decisions. Vertical precedent concerns lower courts following decisions of superior courts; horizontal precedent concerns a court’s treatment of its own previous decisions. An earlier ruling may be binding or merely persuasive, depending on the deciding court’s authority and the applicable jurisdictional rules. (law.cornell.edu)
In English legal analysis, the binding principle is generally the ratio decidendi, the legal reasoning necessary to the decision. Obiter dicta are observations that do not form part of that binding rationale, although they may carry persuasive weight. Identifying the ratio requires reading the judgment in relation to its issues and material facts; it is not simply a matter of extracting any general statement made by a judge. (supremecourt.uk)
Courts can distinguish an earlier case when relevant factual or legal differences make its rule inapplicable. Courts with appropriate authority can also overrule previous decisions, subject to the jurisdiction’s rules governing precedent. Common-law development therefore combines continuity with controlled revision. The operation of precedent is not identical in every common-law jurisdiction, particularly concerning when a highest court may depart from its own decisions. (law.cornell.edu)
Legislation and equitable remedies
Common law operates alongside legislation, not as an alternative to legislative government. Legislatures can codify, modify, or replace judicially developed rules. Courts then interpret and apply the resulting statutes, so precedent also shapes the meaning of legislation. “Case law” is consequently broader than common law in its narrow sense: judicial decisions may concern enacted rules rather than independently developed doctrines. (law.cornell.edu)
Equity supplied remedies for circumstances in which ordinary legal relief was inadequate. These include an injunction, directing a party to act or refrain from acting, and specific performance, requiring fulfilment of a contractual obligation. Equity also developed rules concerning trusts. These remedies remain significant in litigation involving contracts and property, even where the same courts administer legal and equitable claims. (fjc.gov)
Geographic distribution and jurisdictional variation
The common-law tradition extends beyond England to jurisdictions including the United States, Canada, Australia, New Zealand, and India. Their courts sometimes consult one another’s judgments, but shared legal ancestry does not create a single international body of binding common law. Foreign decisions can inform reasoning without automatically controlling the outcome. (supremecourt.uk)
Canada illustrates coexistence between traditions. Quebec generally uses civil law for private-law matters, while the other provinces and territories use common law. Federal legislation addressing private law must accommodate this difference. The arrangement is known as bijuralism and does not imply that every area of Quebec law follows a separate civil-law framework. (justice.gc.ca)
In the United States, federalism makes the distinction between state and federal law especially important. Common-law development occurs predominantly at state level. In Erie Railroad Co. v. Tompkins (1938), the Supreme Court rejected federal “general common law.” Under the Erie doctrine, federal courts exercising diversity jurisdiction generally apply state substantive law, including state judicial decisions. Limited areas of federal common law nevertheless remain; Erie did not eliminate every form of federal judicial rulemaking. (fjc.gov)