RPG Pre-History
RPG History begins in an oft-unmentioned "pre-history". When considering what RPG's are, it is important to consider it's entire history. Therefore, RPG history begins with Gary Gygax.
Gary Gygax was a part of a war-gaming group. These war games were combat-oriented and many of them were nothing more than a complex battle system. He expanded this into Chainmail, which set battles between fantasy characters in underground settings. Chainmail was very similar to turn-based strategy RPG's today — without the plot or computerized opponents — and at this point, the only part of traditional RPG's to make the jump to console-style RPG's — the battle system.
Later, similar rules were included in Dungeons and Dragons, the first traditional RPG. An element of role-playing was also included. This was not (and cannot be) included in computerized RPGs.
Birth of the Computer RPG
Computer RPGs were nothing like what most people think of an RPG today. Most of them attempted to emulate the battle system rules of games like Dungeons or Dragons. The official Dungeons and Dragons games, often based on the books and settings of the system, were quite popular. Because of this connection with Dungeons and Dragons and similar traditional RPGs, the name was used to describe later, non-connected games.