The francophone Swiss Rodolphe Töpffer produced comic strips beginning in 1827, and published theories behind the form. Cartoons appeared widely in newspapers and magazines from the 19th century. The success of Zig et Puce in 1925 popularized the use of speech balloons in European comics, after which Franco-Belgian comics began to dominate. The Adventures of Tintin, with its signature clear line style, was first serialized in newspaper comics supplements beginning in 1929, and became an icon of Franco-Belgian comics.