"Fine Otto Müller. Lyricist but still human, very thin lips", reported Ernst Ludwig Kirchner in a letter to Erich Heckel from Dresden to Dangast on May 22, 1910. He wrote about their first meeting at the Berlin exhibition at Galerie Macht, which showed works by those rejected from the Berlin Secession. (Ernst Ludwig Kirchner. Der gesamte Briefwechsel, ed. by Hans Delfs, Zurich 2010, no. 64) In October 1911, after he had traveled to Prague with Kirchner during the summer, in order to, among others, recruit the Czech painter Bohumil Kubišta for the artist group, Otto Mueller returned to Berlin and moved into a new studio on Varziner Strasse 8 in Berlin-Friedenau. Heckel took over his old studio on Mommsenstraße 60 (today Markelstraße) in Steglitz. Heckel had left Dresden for Berlin in December and also set up the artist group's office there. Otto Mueller painted life-size standing and sitting nude figures as well as a painting of his wife Maschka, whom he had married in 1905, on the walls of his studio, additionally, he decorated the apartment with batik cloths. Ernst Gosebruch, progressive director of the Municipal Art Collections in Essen and an advocate of Expressionism, visited the painters of the "Brücke" in Berlin in the winter of early 1912 and reported on Mueller's studio: "The unbelievable sparseness of these rooftop quarters did not strike that hard upon entering. Otto Mueller's solemn friezes, for instance, gave his rooms something, one must say, regal, a grand style, behind which no one would suspect lack at all." (Quoted from: Lothar Günther Buchheim, Die Künstlergemeinschaft Brücke, Feldafing 1956, p. 60)

In the studio Kirchner sketched the encounter at the coffee table in a room with dormers, fabric panels and pictures on the walls with a quick pen. A coffee set and a kerosene lamp with glass cylinder and shade can be seen on the table. Three people are sitting at the table, Otto Mueller, his back turned to us, to his left presumably Maschka, his wife, and to his right Kirchner's companion, Erna or Gerda Schilling? A photograph of Kirchner, also taken in Mueller's studio, shows Kirchner himself and Gerda Schilling, Erna's sister, in addition to the Mueller couple. (Fig.) Kirchner met the siblings in October 1911, shortly after he had moved to Berlin. Over the following years they became part of the artist's work as models, either alone or together, they were the protagonists of the so-called "Street Pictures." Erna remained Kirchner's partner until his death in 1938, while Gerda's traces disappeared in 1927. The friendship between Kirchner and Mueller in particular developed in a casual manner; as the oldest member of the artist group there was no competitive behavior towards Heckel, Kirchner, Pechstein and Schmidt-Rottluff; it just wasn’t Mueller's nature. On October 15, 1930, Kirchner described his memories of his former companion, who had just died on September 24 to his collector Carl Hagemann, who also owned a couple of works by Mueller: "I was so deeply moved by his early death. We were very close for years before the war and then were separated by the circumstances. [..] We were also shared the sensual adoration of women and the appreciation of elegance, except that he was a stronger advocate of traditional relationships, while I preferred the free companionship. I liked him best of all the artists I knew, because he was the only one who had a noble, decent, upright character, a gentleman and not a bootlicker or careerist. He fought for free art and was uncompromising. His imagination may have been smaller, but all his works are of a high quality, and they are truly free works of art and genuine, too, because they grew from the soil of his view of the world. He is our Corot." (Ernst Ludwig Kirchner. Der gesamte Briefwechsel, ed. by Hans Delfs, Zurich 2010, no. 2452) [MvL]