What was the cause of this last and most perilous phase? It was the collapse of Russia, produced by the Bolshevist _coup d’état_ in Petrograd on November 7th, 1917. On that day, Lenin achieved the purpose for which the Germans had given him his passports into Russia. He destroyed Kerensky, who combined revolution with national war, and he substituted a policy of international peace combined with civil war. Both edges of that policy were sharpened to the destruction of Russia as a war power, and on December 20th Mr. Lloyd George warned the House of Commons that the collapse of Russia, following on the Italian defeat, would require a new and still greater output of man-power by Great Britain. A Bill for that purpose was introduced into the House of Commons on January 14th, abolishing almost the last exemptions from military service. Events in Russia moved swiftly. On November 21st the Bolshevists made to the Germans a definite proposal for armistice, and peace negotiations began at Brest-Litovsk on December 2nd. The Bolshevists twice broke up the Constituent Assembly at Petrograd by force of arms. The Germans put forward peace terms of such severity that even the Bolshevists were dismayed, and Trotsky attempted to declare peace without signing the treaty. Thereupon the Germans advanced their armies into Russia, meeting with no resistance, and occupying Minsk in the north and Kieff in the south. Powerless in the face of this invasion, the Bolshevists signed the peace treaty on March 2nd, surrendering Lithuania, Finland, the Ukraine, Poland, and the Baltic Provinces, promising demobilisation of their armies and internment of their ships. Russia was out of the war. On March 5th the Germans followed this up by signing peace with Rumania, and on March 6th they signed peace with Finland. Their great armies in the East of Europe were now free to work their will on the West.