Besides religious laws such as the Torah, important codifications were developed in the ancient Roman Empire, with the compilations of the Lex Duodecim Tabularum and much later the Corpus Iuris Civilis. These codified laws were the exceptions rather than the rule, however, as during much of the ancient Roman laws were left mostly uncodified.
The first permanent system of codified laws could be found in China, with the compilation of the Tang Code in CE 624. This formed the basis of the Chinese criminal code, which was then replaced by the Great Qing Legal Code, which was in turn abolished in 1912 following the Xinhai Revolution and the establishment of the Republic of China. The new laws of the Republic of China were inspired by the German codified work, the Bürgerliches Gesetzbuch.. A very influential example in Europe was the French Napoleonic code of 1804.
Contrary to popular belief, the common law has been codified in many jurisdictions in many areas; examples include the Law of General Obligations of New York State, the English law relating to Marine insurance, which was originally judge-made common law, and the California Civil Code.
In civil law jurisdictions, codification has also occurred in many areas. Statutes of the Grand Duchy of Lithuania were most notable codifications of law in the Central and Eastern Europe of the 16th century. The codification movement developed out of the philosophy of the Enlightenment and began in several European countries during the late 18th century (see civil code). However, it only gained significant momentum with the enactment of the French Napoleonic Code in 1804.
In the United States, acts of Congress, such as federal statutes, are published chronologically in the order in which they become law — often by being signed by the President, on an individual basis in official pamphlets called "slip laws," and are grouped together in official bound book form, also chronologically, as "session laws." The "session law" publication for Federal statutes is called the United States Statutes at Large. Any given act may be only one page long, or hundreds of pages, in length. An act may be classified as either a "Public Law" or a "Private Law."
Because each Congressional act may contain laws on a variety of topics, many acts, or portions thereof are also rearranged and published in a topical, subject matter codification. The official codification of Federal statutes is called the United States Code. Generally, only "Public Laws" are codified. The United States Code is divided into "titles" (based on overall topics) numbered 1 through 50. Title 18, for example, contains many of the Federal criminal statutes. Title 26 is the Internal Revenue Code.
Even in code form, however, many statutes by their nature pertain to more than one topic. For example, the statute making tax evasion a felony pertains to both criminal law and tax law, but is found only in the Internal Revenue Code. Other statutes pertaining to taxation are found not in the Internal Revenue Code but instead, for example, in the Bankruptcy Code in Title 11 of the United States Code, or the Judiciary Code in Title 28.
Further, portions of some Congressional acts, such as the provisions for the effective dates of amendments to codified laws, are themselves not codified at all. These statutes may by found by referring to the acts as published in "slip law" and "session law" form. However, commercial publications that specialize in legal materials often arrange and print the uncodified statutes with the codes to which they pertain.
In the United States, the individual states, either officially or through private commercial publishers, generally follow the same three-part model for the publication of their own statutes: slip law, session law, and codification.