It was first published in the United States by California Pacific Computer Company, which registered a copyright for the game on September 2, 1980[1] and officially released it in June 1981.

Ultima revolves around a quest to find and destroy the Gem of Immortality, which is being used by the evil wizard Mondain to enslave the lands of Sosaria.

[4] The game was one of the first definitive commercial computer RPGs, and is considered an important and influential turning point for the development of the genre throughout years to come.

[4] In both scenarios the player character is controlled with the keyboard directional arrows, and shortcut keys are used for other commands, such as A for attack and B for board.

[8] Character creation at the start of Ultima is not unlike a simplified version of traditional tabletop role-playing games.

[8] Once this portion of character creation has been completed, the player is given a choice of four races: Human, Elf, Dwarf and Bobbit (a hobbit-like creature).

Hit points can be obtained in a variety of ways, including the acts of emerging alive from a dungeon and of giving tribute payment to one of the eight lords of Sosaria.

Coin is used to buy things in the game world, such as weapons, spells, and food, and can be obtained by defeating monsters or rescuing princesses from castles.

The combat was reminiscent of Doug Neubauer's Star Raiders, released a couple of years earlier for the Atari 8-bit computers, that both programmers enjoyed playing.

[10] The player participates in a real-time space combat environment, confronted with enemy spaceships that they must shoot down in order to progress further along the story.

Fulfilling the former type of quest gives stat boosts; the latter gains the player an important item needed to reach the endgame.

According to the game's back story, Mondain created an evil gem over 1000 years ago that granted him immortality.

[12] Since then, Mondain has released monsters and beasts upon the land that ravage the villages and towns of Sosaria and cause most of the nobles to bicker amongst themselves.

[3] In an effort to stop Mondain's dominion, Lord British searches for a person to bring about the wizard's end.

[3] The player is informed that the only way to defeat Mondain is to travel back in time and kill him before the gem of immortality is created.

In exchange for the gem, the lord will ask the player to complete a quest that involves traveling into a dungeon and killing a specific creature.

[18] Towns, quests, a plot and a user interface were all added to the original Akalabeth code before Ultima was completed.

[5][22] Unlike Akalabeth, the commercial sale of which was an afterthought to a hobbyist endeavor, Ultima was approached with a much more professional attitude right from the start of the project.

[29] Later releases include the 1989 version for the MSX2, published only in Japan by Pony Canyon,[29] and an Apple IIGS specific port in late 1994 by Vitesse.