Most of these German citizens were ultimately absorbed by the Polish population. But they were not the only Germans with whom the Polish State had now to deal. In the first year of the 13th century, a powerful crusading order, the Knights of the Sword, had been established in Livonia for the reduction of the pagan Letts, and, in 1208, the still stronger Teutonic Order was invited by Duke Conrad of Masovia to settle in the district of KuLm (roughly corresponding to modern East Prussia) to pro tect his territories against the incursions of the savage Prussians, a race closely akin to the Lithuanians. Conrad has been loudly blamed by Polish historians for introducing this foreign, and as it ultimately proved, dangerous element into Poland. But the unfortunate prince had to choose between dependence and exter mination, for his unaided resources were powerless against the persistent attacks of the unconquerable Prussians. By the corn pact of Kruschwitz in 1230, the Teutonic Order obtained absolute possession of the maritime district between Pomerania and Cour land, and southwards as far as Thorn. So far were the Poles from anticipating any danger from the Teutonic Order, that, from 1243 to 1255, they actually assisted it to overthrow the independ ent Pomeranian princes, the most formidable opponents of the Knights in the earlier years of their existence. A second Tatar raid in 1259, less dangerous, perhaps, but certainly more ruinous, than the first invasion—for the principalities of Little Poland and Sandomir were systematically ravaged for three months—still further depressed the land, and, at this very time, another enemy appeared in the east—the Lithuanians. (See LITHUANIA.) Casimir the Great, 1333-70.—At the very time when Lithu ania was becoming a compact, united, powerful State, it seemed highly probable that Poland would be completely germanized, like Silesia, or become a part of the new Bohemian empire which Wenceslaus II. (crowned king of Poland in 1300) had inherited from his father, Ottakar II. From this fate she was saved by the valour of Wladislaus Lokietek, duke of Great Poland (1306-33), who reunited Great and Little Poland, revived the royal dignity in 132o, and saved the kingdom from annihilation by his great victory over the Teutonic Knights at Plowce in 1332. The whole reign of Wladislaus I. was indeed an unceasing struggle against all the forces of anarchy and disintegration ; but the fruits of his labours were richly reaped by his son Casimir III. the Great (1333-7o), Poland's first great statesman in the modern sense of the word, who, by a most skilful system of matrimonial alliances, reintroduced Poland into the European system, and gave the exhausted country an inestimably beneficial breathing space of 37 years. A born ruler, Casimir introduced a whole series of administrative and economical reforms. He was the especial protector of the cities and the peasants. It is to him that Poland owed the important acquisition of the greater part of Red Russia, or Galicia, which enabled her to secure her fair share of the northern and eastern trade. In default of male issue, Casimir left the Polish throne to his nephew, Louis of Hungary, who ruled the country (137o-82) through his mother, Queen Elizabeth, Wladislaus Lokietek's daughter. Louis well deserved the epithet of "great" bestowed upon him by his contemporaries; but Poland formed but a small portion of his vast domains, and Polish in terests were subordinated to the larger demands of an imperial policy which embraced half Europe within its orbit.
On the death of Louis there ensued an interregnum of two years marked by fierce civil wars, instigated by duke Ziemovit of Masovia, the northernmost province of Poland, which continued to exist as an independent principality alongside of the kingdom of Poland. Ziemovit aimed at the Polish crown, proposing to marry the infant princess Jadwiga of Hungary, who, as the daughter of Louis the Great and the grand-daughter of Wladislaus Lokietek, had an equal right, by inheritance, to the thrones of Hungary and Poland. By an agreement with the queen mother of
Hungary at Kassa in 1383, the Poles finally accepted Jadwiga as their queen, and, on Feb. 18, 1386, greatly against her will, the young princess was wedded to Jagiello, grand duke of Lithuania, who had been crowned king of Poland at Cracow, three days previously, under the title of Wladislaus II.
The union of Poland and Lithuania as separate States under one king had been brought about by their common fear of the Teutonic Order. Five years after the death of Gedymin (q.v.), Olgierd, the most able of his seven sons, had been placed upon the throne of Lithuania by his devoted brother Kiejstut, and for the next 32 years the two princes still further extended the sway of Lithuania, principally at the expense of Muscovy and the Tatars. Kiejstut ruled the western portion of the land where the Teutonic Knights were a constant menace, while Olgierd drove the Tatar hordes out of the south-eastern steppes, and compelled them to seek a refuge in the Crimea. During Olgierd's reign the southern boundaries of Lithuania touched the Black sea, includ ing the whole tract of land between the mouth of the Bug and the mouth of the Dnieper. Olgierd was succeeded by his son Jagiello as grand duke in 1377, while Kiejstut was left in posses sion of Samogitia, Troki and Grodno ; but the Teutonic Order, alarmed at the growth of Lithuania, succeeded in estranging uncle and nephew, and Kiejstut was treacherously assassinated by Jagiello's orders, at Krewo, on Aug. 15, 1382. Three weeks later Jagiello was compelled to cede Samogitia, as far as the Dubissa, to the Knights, and, in the following year they set up against him Kiejstut's son Witowt. At this point Jagiello made peace with his cousin, restored him his patrimony, and made overtures to Poland for the hand of Jadwiga, and received the Polish crown along with it, as already mentioned.
The paucity and taciturnity of our sources make it impossible to give anything like an adequate picture of Old Poland during these centuries. External pressure, here as elsewhere, created a patriotic military caste, and the subsequent partitional period, when every little prince had his own separate court, still further established the growing influence of the szlachta, or gentry. The first authentic pasta conventa made between the Polish nobility and the Crown dates from the compact of Kassa (Sept. 17, when Louis of Hungary agreed to exempt the szlachta from all taxation, except two Polish groschen per hide of land, and to compensate them for the expenses of all military service rendered beyond the confines of the realm. The clergy received their chief privileges much earlier. It was at the synod of Leczyca, nearly a century before the compact of Kassa, that the property of the church was first safeguarded against the encroachments of the State. The beneficial influence of the Church of Poland in these early times was incalculable. To say nothing of the labours of the Cistercians as colonists, pioneers and church-builders, or of the missions of the Dominicans and Franciscans, the church was the one stable and unifying element in an age of centrifugal par ticularism. Its frequent synods represented the whole of Poland, and kept alive, as nothing else could, the idea of national solidar ity. Moreover the clergy, to their eternal honour, consistently protected the lower from the tyranny of the upper classes.