A few theories about early sans-serifs now known to be incorrect may be mentioned here. One is that sans-serifs are based on either "fat face typefaces" or slab-serifs with the serifs removed. It is now known that the inspiration was more classical antiquity, and sans-serifs appeared before the first dated appearance of slab-serif letterforms in 1810. The Schelter & Giesecke foundry also claimed during the 1920s to have been offering a sans-serif with lower-case by 1825. Wolfgang Homola dated it in 2004 to 1882 based on a study of Schelter & Giesecke specimens; Mosley describes this as "thoroughly discredited"; even in 1986 Walter Tracy described the claimed dates as "on stylistic grounds...about forty years too early".