There’s an article up at Gamasutra — the latest in the site’s ongoing Game Design Essentials series — which discusses twenty RPGs, examines what makes them significant, and explains why they should be considered essential experience game designers. The second entry on the list, after the Wizardry series, is the Ultima series:

The Ultima series is the forefather of the vast main category of CRPGs.

Wizardry didn’t change much among the majority of its lifespan, but the Ultima games changed greatly during their early years. This article is mostly concerned with the earlier games, but the flow of its design can be traced up as far as Ultima VII, generally regarded as the zenith of the series’ popularity and influence.

The first games (technically the first Ultima game was Akalabeth) were dungeon-crawly things, but without the benefit of Wizardry’s many specials or mapping tricks. Dungeons were primarily just places with monsters, and the occasional important plot item. They tend to be less interesting places than Wizardry’s treacherous dungeons.

That’s okay however, for Ultima brought us what has become known as an “overworld,” a tile-based world in which the dungeons are set as special locations. It also brought us real towns, and a routine for speaking with people (instead of treating them as another thing to handle with specials).

Later Ultimas would even allow for interactive conversations with characters. This was usually handled using keywords, where speaking with people would reveal some things that could be asked about, either with that character or others.

Okay, technically, treating the entirety of the Ultima series (or the Wizardry series, for that matter) as one of twenty RPGs on a list is kind of…cheating, really, seeing as how the series comprises quite a number of games. Then too, though, each Ultima brought something new and innovative to the RPG space, did something to establish a convention that is probably still in use today in some form…so one can kind of see Harris’ point in listing the series as one entire entry.