GURPS is the Steve Jackson Games version of Metagaming's The Fantasy Trip, which was composed of Melee, a combat system, and Wizard, a magic system. I actually started off playing RPGs with The Fantasy Trip, since it was more "realistic" than D&D, as your dexterity and agility rather than your strength determined if you hit or missed your opponent. Strength determined the amount of damage while your intelligence determined how many spells you could cast but with a spell point system rather than the Dying Earth system of D&D.
Steve Jackson worked for Metagaming during the late 70s and early 80s, coming up with the concepts of Ogre and Car Wars while there as well as much of The Fantasy Trip. When Metagaming went out of business, Jackson took Car Wars and Ogre to his new company, Steve Jackson Games. he attempted to purchase The Fantasy Trip as well but the owner of the company reportedly asked in excess of $100,000 for the rights. Instead, Jackson took the core concepts of TFT and expanded them into GURPS, the Generic Universal Role Playing System.