At the same time the Bolsheviki began a campaign of denunciation against Makhno and his _povstantsi_. The Communist press accused him of having treacherously opened the southern front to Denikin, and branded Makhno's army a bandit gang and its leader a counter-revolutionist who must be destroyed at all cost. But this "counter-revolutionist" fully realized the Denikin menace to the Revolution. He gathered new forces and support among the peasants and in the months of September and October, 1919, his campaign against Denikin gave the latter its death blow on the Ukraina. Makhno captured Denikin's artillery base at Mariopol, annihilated the rear of the enemy's army, and succeeded in separating the main body from its base of supply. This brilliant manoeuvre of Makhno and the heroic fighting of the rebel army again brought about friendly contact with the Bolsheviki. The ban was lifted from the _povstantsi_ and the Communist press now began to eulogize Makhno as a great military genius and brave defender of the Revolution in the Ukraina. But the differences between Makhno and the Bolsheviki were deep-rooted: he strove to establish free peasant communes in the Ukraina, while the Communists were bent on imposing the Moscow rule. Ultimately a clash was inevitable, and it came early in January, 1920. At that period a new enemy was threatening the Revolution. Grigoriev, formerly of the Tsarist army, later friend of the Bolsheviki, now turned against them. Having gained considerable support in the south because of his slogans of freedom and free Soviets, Grigoriev proposed to Makhno that they join forces against the Communist régime. Makhno called a meeting of the two armies and there publicly accused Grigoriev of counter-revolution and produced evidence of numerous pogroms organized by him against the Jews. Declaring Grigoriev an enemy of the people and of the Revolution, Makhno and his staff condemned him and his aides to death, executing them on the spot. Part of Grigoriev's army joined Makhno. Meanwhile, Denikin kept pressing Makhno, finally forcing him to withdraw from his position. Not of course without bitter fighting all along the line of nine hundred versts, the retreat lasting four months, Makhno marching toward Galicia. Denikin advanced upon Kharkov, then farther north, capturing Orel and Kursk, and finally reached the gates of Tula, in the immediate neighbourhood of Moscow. The Red Army seemed powerless to check the advance of Denikin, but meanwhile Makhno had gathered new forces and attacked Denikin in the rear. The unexpectedness of this new turn and the extraordinary military exploits of Makhno's men in this campaign disorganized the plans of Denikin, demoralized his army, and gave the Red Army the opportunity of taking the offensive against the counter-revolutionary enemy in the neighbourhood of Tula.