Who dated Marianne Von Werefkin?

Alexej Georgewitsch von Jawlensky (Russian: Алексе́й Гео́ргиевич Явле́нский, romanized: Alekséy Geórgiyevich Yavlénskiy; 13 March 1864 – 15 March 1941), surname also spelt as Yavlensky, was a Russian expressionist painter active in Germany. He was a key member of the New Munich Artist's Association (Neue Künstlervereinigung München), Der Blaue Reiter ("The Blue Rider") group, and later Die Blaue Vier ("The Blue Four").