Around the beginning of the 20th century, Karlsbad was one of three Bohemian spa resort cities. (The other two were Marienbad and Franzenbad.) As a result, many wealthy visitors came to the town. Oyster plates were a popular souvenir. Since many Jews visited the town—especially in 1921 and 1923, when Karlsbad was the location of a major Zionist conference—some of these oyster plates were adapted for the Jewish tourists who would have wanted a religious ritual object.