 Several works were acquired through his contacts with contemporary artists such as Auguste Rodin, Constantin Meunier and Max Klinger, adding a modern perspective.In 1891, he opened a collection of casts, which served as a model when Ivan Vladimirovich Tsvetayev established the Pushkin Museum.Finally, in 1900, he opened the Sammlung Treus (Treu's Collection) to document the history of sculpture.