Grobstein

In the fall of 1904, Arnold Schönberg, at the age of 30, began teaching private lessons, taking on as his first students Webern, Jalowitz, Berg, and Stein.
Webern and Berg wouldl prove to be the most talented of all of Schönberg's pupils, and the three of them ackowledged that together they took part in the break away from tonality.

On October 15, Schönberg began teaching a 4-hour harmony/counterpoint course from 5:00-9:00 in the evenings at the Girl's Gymnasium in central Vienna (Wallnerstrasse 2, I District.), basing his course on Bellermann's 1862 counterpoint treatise Der Contrapunkt (most likely the 4th edition published in 1901). [Monson 1979, p. 27]

Schönberg served on active duty twice during the war, and his major work during the following decade was on Die Jakobsleiter ['Jacob's Ladder'], which remained unfinished.

In 1908, Mathilde Zemlinsky left Arnold Schönberg and their two children, daughter, Gertrude, and son, Georg, to live with painter, Richard Gerstl.
After a few months, she was persuaded to return for the sake of the children; Gerstl committed suicide.
Mathilde Zemlinsky remained with Schönberg until her death in 1923.

Arnold Schönberg founded the Society for Private Performances in Wien, in order to rehearse and perform difficult contemporary music.