The artist was part of the group:

The Berlin Secession was an art movement established in Germany on May 2, 1898. Formed in reaction to the Association of Berlin Artists, and the restrictions on contemporary art imposed by Kaiser Wilhelm II, 65 artists "seceded," demonstrating against the standards of academic or government-endorsed art. The movement is classified as a form of German Modernism, and came on the heels of several other secessions in Germany, including Jugendstil and the Munich Secession.