Depends where you want to draw the line. You could trace the lineage all the way back to Rogue with its grid map where the player is fixed to the grid and moves in full block increments. Then you had those 3D maze games where you were still on the grid and stuck moving in cardinal directions, but you got a 3D representation of the area. Then Wolfenstein allowed the player to move freely on the same grid map. Finally Doom (finally!) dispensed with the grid and made the map out of vectors.

Not knocking your history, but I gotta say that Wolfenstein-3D was like nothing I'd ever seen...and I played the original Wolfenstein on the Apple II--and the original Wizardry as well, which is a lot more to the point than Rogue IMHO. The Wizardry map grid and the Wolfenstein-3D map grid are really similar, now that I think about it.