The Sixth Congress of the RSDLP (b) was held semi-legally in Petrograd from July 26 (August 8) to August 3 (16), 1917. The press announced only the convening of the congress, but did not indicate the place of its meetings. The threat of closing the congress by the Provisional Government was so real that it was necessary not only to change the place of meetings of the congress, but also to hold elections of members of the Central Committee long before its end, as well as to reduce the duration of the congress.