Quintus Prolog

Originally developed by Quintus Computer Science, it is currently maintained by SICS.

Quintus Prolog was first introduced in 1984 as an implementation of the recently proposed Warren Abstract Machine by Quintus Computer Science, which had been founded for this purpose by David H. D. Warren, William Kornfeld, Lawrence Byrd, Fernando Pereira and Cuthbert Hurd.

[1] Quintus was sold to Intergraph Corporation in 1989,[2][3] and was eventually acquired by SICS in 1998.

[1] After several of its features were amalgamated into their Prolog implementation SICStus, its final version release was Quintus 3.5 in 2003.

[1] In addition, while the module system envisaged by the ISO standard deviates from that of Quintus, the Quintus module system is in fact more widely adopted by modern Prolog implementations than that mandated by ISO.