Konrad now found himself in a very awkward position; he had introduced of his own will a foreign and hostile power which had all Western Europe and the Holy See to support it, which had unbounded means of discrediting the Poles and putting them in the wrong before the world; and these means the order never failed to use. In half a century after their coming the knights, by the aid of volunteers and contributions from all Europe, had converted Prussia, and considered Poland and the adjoining parts of Lithuania as sure conquests to be made at their own leisure and at the expense of all Western Christendom.

The first Polish territory acquired was Pomerania. The career of the knights was easy and successful till the union of Poland and Lithuania in 1386. In 1410, at the battle called by the names both of Grünwald and Tannenberg, the power of the order was broken. Some years later Pomerania was returned to Poland, and the order was allowed to remain in East Prussia in the position of a vassal to the Commonwealth. In this reduced state the knights lived for a time, tried to gain allies, but could not; the most they did--and that was the best for the German cause--was to induce Albert, a member of the Franconian branch of the Hohenzollerns, to become grand master. He began to reorganize the order, and tried to shake off allegiance to Poland; but finding no aid in the Empire or elsewhere, he acted on Luther's advice to introduce Protestantism and convert Prussia into a secular and hereditary duchy. This he did in 1525. Poland, with a simplicity quite equal to that of Konrad, who called in the order at first, permitted the change. The military monks married, and were converted into hereditary nobles. Albert became Duke of Prussia, and took the oath of allegiance to Poland. Later the Hohenzollerns of Brandenburg inherited the duchy, became feudatories of Poland as well as electors at home. This was the position during the war between Sweden and Poland described in THE DELUGE. Frederick William, known as the Great Elector, was ruling at that time in Brandenburg and Prussia. He acted with great adroitness and success; paying no attention to his oath as vassal, he took the part of one side, and then of the other when he saw fit. He fought on the Swedish side in the three days' battle around Warsaw in which Yan Kazimir was defeated. This service was to be rewarded by the independence of Prussia.

Hardly had the scale turned in favor of Poland when the Great Elector assisted Yan Kazimir against Sweden; and in the treaty of Wehlau (1657) Poland relinquished its rights over Prussia, which thus became sovereign and independent in Europe. This most important change was confirmed three years later at the peace of Oliva.

Frederick, son of the Great Elector, was crowned "King in Prussia" at Königsberg in 1701. The Elector of Brandenburg became king in that territory in which he had no suzerain.

At the first division of Poland, Royal Prussia of The Deluge, the territory lying between the Vistula and Brandenburg, went to the new kingdom; and Brandenburg, Pomerania, and Prussia became continuous territory.

The early success of the Teutonic Knights was so great that in the third half century of their rule on the Baltic their power overshadowed Poland, which was thus seriously threatened. Toward the end of the fourteenth century, however (1386), the Poles escaped imminent danger by their union with Lithuania and Russia. Through this most important connection they rose at once from a position of peril to one of safety and power.

This union, brought about through the marriage of the Polish princess Yadviga to Yagyello, Grand Prince of Lithuania, and by exceedingly adroit management on the part of the Polish nobles and clergy, opened to the Poles immense regions of country and the way to vast wealth. Before the union their whole land was composed of Great and Little Poland, with Mazovia (see map); after the union two thirds of the best lands of pre-Tartar Russia formed part of the Commonwealth.

Since Poland managed to place and maintain itself at the head of affairs, though this roused at all times opposition of varying violence in the other two parts of the Commonwealth, the social ideals and political structure of Poland prevailed in Lithuania and Russia, so far as the upper classes were concerned. In Lithuania, by the terms of the union, all were obliged to become Catholic; in different parts of Russia, which was Orthodox, the people were undisturbed in their religion at first; but after a time the majority of the nobles became Catholic in religion, and Poles in language, name, manners, and ideas. To these was added a large immigration of Polish nobles seeking advancement and wealth. All Russia found itself after a time under control of an upper class which was out of all sympathy with the great mass and majority of the people.

During the Yagyellon dynasty, which lasted from 1386 to 1572, the religious question was not so prominent for any save nobles; but ownership of their own land and their own labor was gradually slipping away from the people. During the reign of Sigismund III. (1587-1632), religion was pushed to the foreground, the United Church was brought into Russia; and land and religion, which raise the two greatest problems in a State, the material and the spiritual, were the main objects of thought throughout Russia.

Under Vladislav in 1648 the storm burst forth in Southern Russia. There was a popular uprising, the most wide-spread and stubborn in history, during which the Poles lost many battles and gained one great victory, that of Berestechko; the Southern Russians turned to the North, and selected the Tsar Alexai Mihailovich as sovereign.

Jan. 8, 1654, there was a great meeting in Pereyaslav,^[2] at which Bogdan Hmelnitski, hetman of the Zaporojian army and head of all Southern Russia, after he had consulted with the Cossacks, took his place in the centre of the circle, and in presence of the army, the people, and Buturlin, the envoy of Alexai Mihailovich, said:--

"Gentlemen, Colonels, Essauls, Commanders of hundreds, the whole Zaporojian army, and all Orthodox Christians,--You know how the Lord delivered us from the hands of our enemies who persecuted the Church of God and were envenomed against all Christians of our Eastern Orthodoxy. We have lived six years without a sovereign, in endless battles against our persecutors and enemies who desire to root out the church of God, so that the Russian name may not be heard in our land. This position has grown unendurable, and we cannot live longer without a sovereign. Therefore we have assembled a council before the whole people, so that you with us may choose from four sovereigns that one whom you wish. The first is the Sovereign of Turkey, who has invited us under his authority many times through his envoys; the second is the Khan of the Crimea; the third the King of Poland, who, if we wish, may receive us into former favor; the fourth is the Orthodox sovereign, the Tsar and Grand Prince Alexai Mihailovich, the sole ruler of all Russia, whom we have been imploring six years with unceasing petitions. Choose whom you like. The Sovereign of Turkey is a Mussulman; you all know how our brethren, the Greeks, Orthodox Christians, suffer, and what persecution they endure from godless men. A Mussulman also is the Khan of the Crimea, whom we took into friendship of necessity, by reason of the unendurable woes which we passed through. Of persecutions from Polish lords it is needless to speak; you know yourselves that they esteemed a Jew and a dog more than a Christian, our brother. But the great Orthodox sovereign of the East is of one faith with us, one