There’s an abundance of information on Ultima available on the internet and also in physical form by much more knowledgeable people than myself, like Stephen Emond’s Ultima: the Ultimate Companion Guide and Ultima: the Ultimate Collector’s Guide alongside Andrea Contato’s recent book Through the Moongate, so I have decided not to write a whole bunch, it’s more of an overview of the Ultima (I) titles in my collection.

In 1980 Al Remmers, the founder of California Pacific Computer Company received a copy of Richard Garriott’s Akalabeth. Remmers, impressed by the high schoolers’ hobbyist project offered Garriott a distribution deal with a $5 royalty for every sold copy. While there seems to be a bit of discrepancy around the actual number of sold copies by California Pacific, different sources suggest a number anywhere between 10.000 and 30.000. Regardless, the fact that Garriott’s game, which was essentially created for his own enjoyment, was able to achieve such success raised the question of how much a professionally-made game could accomplish.

California Pacific’s re-release of Akalabeth: World of Doom from 1981.
The demon artwork by Denis Loubet was initially made as a cover for The Space Gamer Magazine

The Space Gamer number 28 from May/June 1980 featuring Denis Loubet’s demon cover art

While a sophomore at the University of Texas, Garriott started working on a much more ambitious and professional game than Akalabeth. A game that eventually would become Ultima. Much of the inner workings of Akalabeth were reused and towns, quests, and a user interface alongside sci-fi-inspired elements were added. Garriott completed Ultima in under a year, intending to release it under the title Ultimatum. However, to avoid any confusion or even legal disputes with J. Michael Hemphill’s 1979 board game Ultimatum: A Game of Nuclear Confrontation, the title was changed to Ultima by the suggestion of Remmers.
Ultima debuted on the Apple II in the early summer of 1981 and sold around 20,000 copies within its first year. Ultima would eventually go on to sell around 50,000 copies.

The very first release of Ultima, published for the Apple II in 1981 by California Pacific Computer Company. The game was only released for the Apple II and was programmed in Apple BASIC (with a few Assembly routines by Kenneth Arnold) which essentially made it impossible to port to other systems without rewriting the entire game

Ultima was re-released later in 1981 under California Pacific’s Progame label

Garriott knew that he had pushed BASIC to its limit with Ultima and decided to use his summer break in 1981 to study assembly language before starting the development of his next Ultima. In the fall Garriott returned to college where he would spend most of his time working on what would become Ultima II. Around the same time, financial issues started to surface at California Pacific, resulting in not fully paid royalties, which led to a fallout between Garriott and Remmers. Although highly unlikely, rumors had it that Remmers had been using Garriott’s royalties to finance his drug habit. Regardless California Pacific was in dire financial straits and failed to pay Garriott what was contractually owed. In late 1981, Remmers’ company went out of business.

Garriott’s success with Akalabeth and Ultima hadn’t gone unnoticed and swiftly the word spread that he was without a publisher. Interested publishers soon learned that Garriott demanded not only a quite high royalty rate but also wanted a detailed high-quality and expensive-to-produce cloth map to be included with Ultima II.
Most potential publishers backed away, only one could agree to Garriott’s “demands”, Ken and Roberta Williams’ On-Line Systems (soon to be Sierra On-Line). Ken struck a deal with Garriott, agreeing to produce the cloth map, and otherwise not interfere with Garriott’s game design.
While Garriott was completing Ultima II On-Line Systems was becoming Sierra On-Line, after Jacky Morby of TA Associates had acquired 20 percent of the company. Ultima II: Revenge of the Enchantress was released in the early autumn of 1982 under the short-lived SierraVenture label.
Sierra On-Line had acquired the legal rights to the Ultima name from Remmers’ defunct California Pacific and spotted an opportunity to monetize on the popularity of the name and re-released Ultima for the Atari 8-bit line of computers in 1983 with the title Ultima I: The Original.

Sierra On-Line re-released Ultima as Ultima I: The Original for the Atari 8-bit in 1983. Sierra contracted with Sigma Micro Systems for them to convert the game and even though the Atari system was superior to that of the Apple II the conversion was made to look as identical to the original release as possible, even down to the color scheme (and glitches).
During this time, Sierra was struggling financially, which may have led to the decision to use the backside of the Ultima II box as cover art for the re-release

Controversy with Sierra over the contract terms and royalties for the IBM PC port of Ultima II, the feeling that Garriott and his Ultima weren’t as appreciated as other designers and their products, and growing tensions between him and Williams led Garriott to look for other opportunities.

With Sierra in the rearview mirror, Garriott teamed up with his father Owen and brother Robert, alongside Chuck Bueche, to found Origin Systems in 1983, where he started to work on Ultima III: Exodus.
After a number of years, the rights returned to Garriott. In 1986, Origin System rewrote the original Ultima with superior graphics, animated tiles, new maps, and other various additions and improvements. It was initially released for the Apple II in December of 1986 as Ultima I: The First Age of Darkness. The following year it was ported to the Commodore 64 and IBM PC.

IBM/PC owners could finally sit down and enjoy the first title in the Ultima series when Origin System published Ultima I: The First Age of Darkness for the platform in 1987

Many subsequent releases were made in later years, including multiple releases for the Japanese market.

In 1988 Ultima I: the First Age of Darkness was converted and published in Japan by PonyCanyon for the PC-8801 system

Ultima I: The First Age of Darkness was also released for the Japanese FM-Towns computer but only as a part of the FM-Towns Ultima Trilogy I-II-III compilation, with upgraded graphics and as the only version of Ultima I to feature music

Andrea Contato’s Through the Moongate – The Story of Richard Garriott, Origin Systems Inc., and Ultima: Part 1 – From Akalabeth to Ultima VI is an excellent read. The book is available from Amazon.
Stephen Emond’s Ultima: the Ultimate Companion Guide and Ultima: the Ultimate Collector’s Guide can be purchased from multiple sources online.