IBM and Compatibles: DOS: MONARCH
Additional Notes:
Ken Sallot writes "Monarch was a forum hack that was developed by a guy in Toronto. I never was quite sure if it was derived from forum directly or from another forum hack (TCS or Emulex). The author quit working on it back in 1988 or 1989."

Steve Holiday has a different set of events: "I worked on Monarch for years. Your site mentions it was developed by a guy in Toronto, which is incorrect. Monarch was started, named, and worked on by me for a couple of years. This all went down in Aurora, Colorado in the 1980s. I did begin development from a very early Forum source and aggressively evolved it."