A body of English law of law which originated with an oral tradition of tribal justice in Britain thousands of years ago and which developed into a unique, cohesive national body of law (the realm) developed and set to writing by English judges over time, and which was eventually imported as the law of British colonies throughout the world such as the United States of America (except Louisiana), Canada (except Quebec) and India.
"The common law is judicially created law that is developed on a case by case basis," wrote Chief Justice Hannah of the Supreme Court of Arkansas in Mason v State.
In R v Rusby, Justice Kenyon wrote:
"The common law, though not to be found in the written records of the realm, yet has been long well known. It is coeval with civilized society itself, and was formed from time to time by the wisdom of man."
Two other sources have contributed to the common law although often described as exceptions thereto: equity and laws imposed by parliament (statutes), both of which have been stated to have, where they differ with the common law, precedence over it.
William Blackstone wrote in his Commentaries on the Laws of England (1756), that common law was:
"... to be found in the records of our several courts of justice in books of reports and judicial decisions, and in treastises of learned sages of the profession, prescribed and handed down to us from the times of ancient antiquity. They are the laws which gave rise and origin to that collection of maxims and customs which is now known by the name of common law."
Because it is not written by elected politicians but, rather, by judges, it is also referred to as unwritten law or lex non scripta.
Judges sought those principles out when trying a case and applied the precedents to the facts to come up with a judgment.
"There was probably never a time when the common law was not in some sense case law....
"(T)the student cites the Roman maxim that one should follow reasons rather than precedents but the master qualifies this by saying that where the reasons for things are obscure, it is enough to follow precedent.
"By the time of Bracton, the influence of judicial practice is clear on the face of the text. The author of the preface stated that he had written the book in order to prevent the newer generation of judges from unwittingly leaving the right course settled by their wise predecessors."
Civil law pundits have had their fun with this; the French, for example, chiding the English with having a case law obsession (la superstitition du cas).
Common law is often contrasted with civil law systems which require all laws to be written in a code or written collection. Common law has been referred to as the:
"... common sense of the community, crystallized and formulated by our ancestors".
The roots of common law can be found in customs for resolving disputes which had evolved in England since the Roman occupation of the Island some 2,000 years ago.
But the Germanic invaders of Britain, as the Romans left, tore up most of the roots Roman law had planted. Gibbon wrote:
"The ferocious Saxons trampled on the laws of Rome. The proceedings of civil and criminal jurisdiction, the titles of honour, the forms of office, the ranks of society, and even the domestic right of marriage, testament and inheritance were finally suppressed, and the indiscriminate crowd of noble and plebian slaves was governed by the traditional customs, which had been coarsely framed for the shepherds and pirates of Germany."
In order to sustain economic order and predictability, the Crown gave its name to (King's Bench) and supported a roving Court which began to amass and consolidate - pick and choose - the customs until a fairly coherent body of law existed, the first version of the common law.
This continued to develop and gained universal acceptance even through, although with some changes to accommodate the conquering Normans in 1099.
Equity law developed after the common law to offset the rigid interpretations medieval English judges were giving the common law.
And yet, ironically, the common law can be said to be more flexible than civil law, civil code and other fully statute-dependent legal systems because the latter are inflexible law built on the past, unable to respond to the present or the future. Many common law lawyers find solace in the words of Allen:
"Common law is living and human. Statutes have neither humanity nor humour."
Or these words of Justice Cockburn in Wason v Walter (1868):
"Whatever disadvantages attach to a system of unwritten law, and of these we are fully sensible, it has at least this advantage, that its elasticity enables those who administer it to adapt it to the varying conditions of society, and to the requirements and habits of the age in which we live, so as to avoid the inconsistencies and injustice which a rise when the law is no longer in harmony with the wants and usages and interests of the generation to which it is immediately applied."
In McFaul v Ramsey, Justice Grier of the United States Supreme Court wrote, of the common law:
"This system, matured by the wisdom of ages, founded on principles of truth and sound reason, has been ruthlessly abolished in many of our States, who have rashly substituted in its place the suggestions of sciolists, who invent new codes and systems of pleading to order. But this attempt to abolish all species, and establish a single genus, is found to be beyond the power of legislative omnipotence....
"The result of these experiments, so far as they have come to our knowledge, has been to destroy the certainty and simplicity of all pleadings, and introduce on the record an endless wrangle in writing, perplexing to the court, delaying and impeding the administration of justice."
In Smith v Harris, Justice Parcq took square aim at Roman law and civil law:
"The common law of this country has been built up, not by the writings of logicians and learned jurists, but by the summings-up of judges of experience to juries consisting of plain men, not usually students of logic, not accustomed to subtle reasoning, but endowed, so far as my experience goes, as a general rule, with great common sense, and if an argument has to be put in terms which only a schoolman could understand, then I am always very doubtful whether it can possibly be expressing the common law."
Statute law started its gradual replacement of much of the common law but not before England had begun to colonize the world. Many jurisdictions began their legal system with whatever the state of the law was at the time their colony was established, thereby perpetuating their union with the British common law system.
For hundreds of years, there were separate courts in England and its dependents: one for common law and one for equity (aka Chancery) and the decisions of the latter, where they conflicted, prevailed.
It is a matter of legal debate whether or not common law and equity are now fused. It is certainly now common to speak of the common law to refer to the entire body of English law, including common law and equity.
As to the flexibility of the common law, Justice McCardie said in Prager (England):
"The object of the common law is to solve difficulties and adjust relations in social and commercial life. It must meet, in so far as it can, sets of fact abnormal as well as usual. It must grow with the development of the nation. It must face and deal with changing or novel circumstances. Unless it can do that, it fails in its function and declines in its dignity. An expanding society demands an expanding common law."
- Allen, C., The Law in the Making (Oxford: Clarendon Press, 1927), page 302.
- Baker, J. H., An Introduction to English Legal History (London: Butterworths LexisNexis, 2002), pages 196-197.
- Buckland, W. and McNair, A., Roman Law and Common Law (Cambridge: University Press, 1965).
- Duhaime, Lloyd, Legal Definition of Lex Non Scripta
- Duhaime, Lloyd, Legal Definition of Lex Scripta
- Gibbon, Edward, The History of the Fall and Decline of the Roman Empire.
- Mason v State, 206 SW 3d 869 (2005)
- McFaul v Ramsey, 61 U.S. 523 (1858)
- Prager v Blatspiel and others 1924 K.B. 599
- R v Rusby  Peake's N.P. Cases 192
- Smith v Harris (1939) 3 All ER 960
- Wason v Walter 4 Q.B. 93 (1868)