A chromatic fantasia is a specific type of fantasia (or fantasy or fancy) originating in sixteenth-century Europe. In its earliest form, it is based on a chromatically descending tetrachord which arises naturally out of the dorian mode. Consequently, the chromatic fantasia is almost invariably in D minor (D-E-F-G-A-B♭-C rather than D-E-F-G-A-B-C) even as late as Bach.