In 1929 , representing the Communist Party , she took a full-time job as a councillor in central Berlin . However , the party conflicts and accompanying purges in Moscow , reflecting Stalin 's conviction - not entirely incorrect - that he might be surrounded by political rivals , found powerful echoes in the German sister party . In February 1930 Frieda Rosenthal was one of the signatories of the " Letter of the 60 " , organised by Erich Raddatz ( and others ) . The letter criticised the direction being taken by the Soviet party leadership under Stalin . However , the party leaderships in the two countries were at this time closely aligned , and after signing the declaration Rosenthal was excluded from the party by the leadership in Berlin . Directly following this she is listed , among the members of the city council , as being " partyless " . Along with others similarly excluded ex-communists , she belonged for some months to the so-called " Group 60 " . In or before 1931 she joined the Social Democratic Party ( '' " Sozialdemokratische Partei Deutschlands " '' / SPD ) . During her final months as a member of the Communist Party she had switched from representing the Lichtenberg electoral district ( District 14 ) in the city council to representing the Kreuzberg electoral district ( District 6 ) , and it was the Kreuzberg district that she continued to represent , as an SPD party member , till 1933
purges
Great Purge
Frieda Rosenthal