Grigory Zinoviev
The Left-SRs formed a coalition with the Bolsheviks in the Council of People's Commissars in late 1917 when, after Lenin's ultimatum to moderate Bolshevik leaders to abandon their attempts to achieve a coalition government with the rest of the more moderate socialist parties, those left the Government (among them, Lev Kamenev, Grigory Zinoviev, Aleksei Rykov and Viktor Nogin).