The original difference is that, historically, common law was law developed by custom, beginning before there were any written laws and continuing to be applied by courts after there were written laws, too, whereas civil law developed out of the Roman law of Justinian's Corpus Juris Civilis (Corpus Iuris Civilis).
In later times, civil law became codified as droit coutumier or customary law that were local compilations of legal principles recognized as normative. Sparked by the age of enlightenment, attempts to codify private law began during the second half of the 18th century (see civil code), but civil codes with a lasting influence were promulgated only after the French Revolution, in jurisdictions such as France (with its Napoleonic Code), Austria (see ABGB), Quebec (see Civil Code of Quebec), Spain (Código Civil), the Netherlands and Germany (see Bürgerliches Gesetzbuch). However, codification is by no means a defining characteristic of a civil law system, as e.g. the civil law systems of Scandinavian countries remain largely uncodified, whereas common law jurisdictions have frequently codified parts of their laws, e.g. in the U.S. Uniform Commercial Code. There are also mixed systems, such as the laws of Scotland, Louisiana, Quebec, Namibia and South Africa.
Thus, the difference between civil law and common law lies less in the mere fact of codification, but in the methodological approach to codes and statutes. In civil law countries, legislation is seen as the primary source of law. By default, courts thus base their judgments on the provisions of codes and statutes, from which solutions in particular cases are to be derived. Courts thus have to reason extensively on the basis of general rules and principles of the code, often drawing analogies from statutory provisions to fill lacunae and to achieve coherence. By