Schick and Moldvay's "Known World" was used as a semi-generic setting in early adventure modules, first mentioned in Module X1, "The Isle of Dread". It was then expanded upon in various "D&D" modules and sources, particularly a series of Gazetteers, many of which originally referred to the setting as "The "D&D" Game World". The first published use of the name "Mystara" came in 1991 from Bruce Heard in the Letters section of his Voyage of the Princess Ark series in "Dragon" magazine. While the name was used in official publications after this, it wasn't until the conversion to AD&D 2nd Edition in 1994 that products were produced under the Mystara title with the official Mystara logo.