In 1959, the Danish company Rialto Film, with its producer Preben Philipsen produced "Der Frosch mit der Maske" (based on "The Fellowship of the Frog"), targeting the German film market. The film turned out to be surprisingly successful and started a veritable fad of crime movies, known as "Krimis" (abbreviation for the German term "Kriminalfilm" or "Kriminalroman") which lasted until significant changes in the direction of the German film industry in the early 1970s occurred. Rialto soon acquired the exclusive rights to nearly all the Wallace novels, founded a German subsidiary company and, unconcerned by the many copycat productions by others, moved towards the artistic and commercial peak of the series in the first half of the Sixties.