Times Of Lore, an RPG that I had for my ZX Spectrum. I loved the game, it was released in 1988. It was viewed top in only two colours as you explored what seemed like a huge world. The only element of character creation was that you got to choose either a barbarian or a knight at the start. This is the first game I ever recall feeling immersed in, simply because it had a day/night cycle, the first game I can remember doing so. You could visit inns for shelter as the wilderness was more dangerous at night and I remember feeling exposed and lonely on the road at night and safe when I reached an Inn.
I think it came with a big fold out map like Skyrim. In my experience any game worth playing or book worth reading comes with a fold out map

Lords Of Chaos and Powermonger also spring to mind.
LOC was a turn based RPG, you were a mage who could cast destruction spells and summon all kinds of creatures, you had to battle another mage on a map that was 8x8 screens. I think it was released around 1990 and I also had it for my Spectrum.
I had Powermonger for the Commodore Amiga. It was an RTS game set in medieval times. Viewed in isometric it centered on conquering towns, resource gathering and army building.
Back then a game like Skyrim was unimagineable, makes me wonder what we'll be playing in 20 years time.