Prolog is a general purpose logic programming language associated with artificial intelligence and computational linguistics.
Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is declarative : the program logic is expressed in terms of relations, represented as facts and rules. A computation is initiated by running a query over these relations.
The language was first conceived by a group around Alain Colmerauer in Marseille, France, in the early 1970s and the first Prolog system was developed in 1972 by Colmerauer with Philippe Roussel.
Prolog was one of the first logic programming languages, and remains the most popular among such languages today, with many free and commercial implementations available. The language has been used for theorem proving, expert systems, as well as its original intended field of use, natural language processing. Modern Prolog environments support creating graphical user interfaces, as well as administrative and networked applications.