Apart from the Ukrainian Cossacks, who were subject to the Polish Government, there were also the so-called Zaporozhian[125] Cossacks, a completely independent military organization which lived beyond the Falls of the Dnieper, in the steppes of so-called New Russia, the present Governments of Yekaterinoslav and Kherson, and indulged in frequent raids upon the Turks and in constant warfare with the Tatars of the Crimea. This military camp, or _syech_,[126] beyond the Falls of the Dnieper attracted many khlops from the Ukraina, who preferred a free, unrestricted military life to the dreary existence of laboring slaves. The syech represented a primitive military republic, where daring, pluck, and knightly exploits were valued above all. It was a semi-barbarous Tatar horde, except that it professed the Greek Orthodox faith, and was of Russian origin, though, by the way, with a considerable admixture of Mongolian blood. The Ukrainian and Zaporozhian Cossacks were in constant relations with each other. The peasants of the Ukraina looked up with pride and hope to this their national guard, which sooner or later was bound to free them from the rule of the Poles and Jews. The Polish Government failed to perceive that on the eastern borders of the Empire a mass of explosives was constantly accumulating, which threatened to wreck the whole Polish Republic. Nor could the Jews foresee that this terrible force would be directed against them, and would stain with blood many pages of their history, serving as a terrible omen for the future. The first warning was sounded in 1637, when the Cossack leader Pavluk suddenly appeared from beyond the Falls in the province of Poltava, inciting the peasants to rise against the pans and the Jews. The rebels demolished several synagogues in the town of Lubny and in neighboring places, and killed about two hundred Jews. The real catastrophe, however, came ten years later. The mutiny of the Cossacks and the Ukrainian peasants in 1648 inaugurates in the history of the Jews of Eastern Europe the era of pogroms, which Southern Russia bequeathed to future generations down to the beginning of the twentieth century. 2. THE POGROMS AND MASSACRES OF 1648-1649 In the spring of 1648, while King Vladislav IV. still sat on the throne of Poland, one of the popular Cossack leaders, Bogdan Khmelnitzki, from the town of Chigirin, in the province of Kiev, unfurled the banner of rebellion in the Ukraina and in the region beyond the Dnieper Falls. Infuriated by the conduct of the Polish authorities of his native place,[127] Khmelnitzki began to incite the Ukrainian Cossacks to armed resistance. They elected him secretly their hetman, and empowered him to conduct negotiations with the Zaporozhians. Having arrived in the region beyond the Dnieper Falls, he organized military companies, and concluded an alliance with the Khan of the Crimea, who entered into a compact to send large troops of Tatars to the aid of the rebels.