The Voyage of the Princess Ark
The Voyage of the Princess Ark was an article series in Dragon Magazine relating to the Dungeons & Dragons setting of Mystara. It was a 2-year-long-running serial (from issue 153, Jan 1990, to issue 188, Dec 1992) charting the titular expedition.
The titular Princess Ark was a skyship - a flying vessel - from the Alphatian Empire, charged with the missing of exploring the distant reaches of Mystera in the pursuit of wealth, alliances and trade agreements on behalf of the Empress of Alphatia. Written in the stylized journal of the Princess Ark's captain, each article ended with new rules for Basic D&D relating to whatever locale had been visited in that month's issue; among other things, this was the birthplace of PC stats for phanatons, lizardfolk, lupins and rakasta, amongst others.
The end result of this was that these articles served as a complement for the various Known World Gazetteers and Hollow World sourcebooks, expanding a Mystaran DM's campaign options.
For a short time after it ended in issue #188, its role was taken up by the Known World Grimoire. The collected Voyage articles were, with some editing and new art & rules, published in the box set "Champions of Mystara: Heroes of the Princess Ark", released in 1993.
The Voyage returned in a single remaining fiction-only article in issue #344, as part of the celebrations for Dragon's 30th anniversary.