Passage: According to the predominant opinion of modern historians, the establishment of a Bolshevik-style council government in Germany on 9–10 November 1918 was impossible. Yet the Ebert government felt threatened by a coup from the left, and was certainly undermined by the Spartakus movement; thus it co-operated with the Supreme Command and the Freikorps. The brutal actions of the Freikorps during the various revolts estranged many left democrats from the SPD. They regarded the behavior of Ebert, Noske and the other SPD leaders during the revolution as an outright betrayal of their own followers.

Question: What happened during the Spartakus movement?
outright betrayal of their own followers.