Iron Crown Enterprises
Iron Crown Enterprises was founded by some sadistic college kids in 1980. They decided that AD&D wasn't clunky enough so they wrote up a couple supplement books to add a more simulationist bent to the game. So if you wanted the ultimate experience in realism, you would go buy a copy of Arms Law, make your attack, then roll on 47 tables to find out what happened. This made the complicated task of swinging a sword much more understandable and it only took 40 minutes! Progress!
When the guys at I.C.E. weren't making your game systems more complicated, they were making their own complicated game systems. Granted, the detail was unsurpassed, but it came at the expense of simplicity and playability. Rolemaster and Spacemaster were undoubtedly detailed and fantastic in scope, but they were beat out by more streamlined games. Iron Crown went bankrupt a few years ago and are now owned by a company named Mjolnir LLC or something or other, before then being passed on to Guild Companion Publications Ltd.
Notably, Iron Crown got the license from the Tolkien estate to make an RPG based on the works of Tolkien. The Middle-Earth Role Playing System, or M.E.R.P., was a more fluid interpretation of their Rolemaster rules, and enjoyed moderate success.
I.C.E. products are still being made and sold, but to a niche market, a niche market known as Rules Lawyers.
For a brief moment, sanity was injected by a small team that looked at the Spacemaster system and said: "The fluff is good, but fuck the rules make my eyes bleed!". They then proceeded to make one of the best (if little known) space fighter skirmish games in the form of Silent Death. Streamlined to the point of having all the information for a ship condensed to one simple understandable side of A4, small 4 on 4 fighter skirmishes take half an hour instead of a bloody week. Unfortunately the fall of I.C.E. led to the demise of this system as well, until it was revived by Metal Express recently. Rejoice, for it is both an excellent game, and the only thing to come out of ICE that is worth playing if you have any sort of social life.