CASIMIR III., called "The Great," king of Poland (1310-1370), the son of Wladislaus Lokietek, king of Poland, and Jadwiga, princess of Kalisch, was born at Kowal in Kujavia in 1310. Casimir belongs to that remarkable group of late medieval sovereigns who may be called the fathers of modern diplomacy, inasmuch as they relegated warfare to its proper place as the instrument of politics, and preferred the council-chamber to the battle-field. He was educated at the court of Charles Robert of Hungary, who had married Casimir's beautiful sister Elizabeth, and who gave his brother-in-law an excellent education under Italian masters. In his youth Casimir was considered frivolous and licentious; while his sudden flight from the field of Plowce, the scene of his father's great victory over the Teutonic knights, argued but poorly for his personal courage. When, therefore, he ascended the Polish throne in 1333, the future of his country, which then consisted of little more than the lately reunited provinces of Great and Little Poland, seemed dark indeed; especially as she was still at war with the Teutonic Order and with John of Luxemburg, king of Bohemia, who claimed the crown of Poland also. Fortunately Casimir was a man of penetrating genius. His father had been a hero who trusted entirely to his sword, yet the heroic struggle of a lifetime had barely sufficed to keep at bay the numerous and potent foes with which Poland was environed. Casimir recognized from the first that further fighting against tremendous odds was unprofitable. A careful, calculating dynastic policy, which aimed at the establishment of an equilibrium by means of prudent compromises and defensive alliances, was, he rightly judged, the best guarantee for the future safety and glory of Poland. Casimir began by tying the hands of the Teutonic Order by the truce of Thorn; he induced the king of Bohemia to relinquish his claims to the Polish throne by consenting to leave him a free hand in Silesia (conference of Trencsén, early in 1335); and subsequently he attended the celebrated congress of Visegrád (November 12-December 3, 1335), where Charles Robert entertained him and the king of Bohemia magnificently. At this congress the differences between Casimir and John of Bohemia were finally adjusted; peace was made between the king of Poland and the Teutonic Order on the basis of the cession of Pomerania, Kulm, and Michalow to the knights, who retroceded Kujavia and Dobrzyn; and the kings of Hungary and Poland further agreed to assist each other in the acquisition of the south-eastern border province of Halicz, or Red Russia (very nearly corresponding to the modern Galicia), in case the necessity for intervention should arise. The Holy See, jealous of the growing power of the house of Luxemburg, attempted to set aside the decrees of the congress of Visegrád, by urging Casimir to take up arms against the knights once more; but Casimir prudently refrained from hostilities, and ultimately compensated himself in the south-east for his losses in the north. To guarantee still further the integrity of Poland, Casimir, who had no male issue, concluded a compact with Charles Robert whereby he recognized Louis, Charles Robert's son, as the successor to the Polish crown; Louis on his part contracting to confirm the privileges of the Polish gentry and clergy, and to rule Poland through natives only.
In 1340 the death of George II. of Halicz, and the ravaging of that fruitful border principality by the Tatars, induced Casimir and Charles Robert to establish their joint influence there, and in 1344 the Red Russian boyar, Demetrius Detko, was appointed starosta, or governor, in the names of the two kings. Nine years later Lubart of Lithuania, who also had claims upon Red Russia, disputed the sway of Poland in that principality. Hungary coming to the assistance of Poland, Lubart was defeated and taken prisoner; but Casimir, anxious to avoid a bloody war with Lithuania's Tatar allies, came to a compromise with Lubart whereby Poland retained Halicz with Lemberg, while Vladimir, Belz, and Brzesc fell to the share of Lithuania. With the Teutonic knights, still Poland's most dangerous foe, Casimir preserved peaceful relations throughout his reign. He kept them within due bounds by using the influence of the Luxemburgers against them at the papal court; but the disputes between Poland and the order were ultimately settled by the peace of Kalisz (July 23, 1343), when the knights engaged for the first time to pay tribute to the Polish crown. John of Bohemia was also a constant thorn in the side of Casimir. Silesia, now split up into seventeen principalities, was the bone of contention between them; and when Casimir suddenly invaded that country, took Wschowa, and made Prince Charles of Bohemia a prisoner, war between the two kingdoms actually broke out and Casimir was besieged in Cracow by the Czechs. But his Hungarian allies hastened to his assistance, and the mediation of the Holy See restored peace in 1346. The death of the adventurous John at Crécy, and the election of his son as emperor, still further improved the situation. Charles IV., a cautious sovereign with many cares, was as anxious for the maintenance of peace as Casimir himself. Thus the relations between them were never very seriously disturbed.
Throughout his reign Casimir never neglected the great work of domestic reform, greatly aided by Jaroslaw Skotowicki, archbishop of Gnesen, formerly a professor at Bologna. The first result of their joint labours was the much-needed codification of the laws of Great and Little Poland in 1347. This was followed by the establishment of a supreme court of appeal in 1357. Towards everything like disorder, tyranny, or aristocratic oppression, Casimir was always inexorably severe; all disturbers of the peace were remorselessly put to death as the worst enemies of their country and he enjoyed in consequence the honourable title of "the Peasants' King." The lawlessness of the nobility was most noticeable in the province of Great Poland, where outrageous acts of violence were of everyday occurrence. To remedy the evil, Casimir drew up and promulgated the severe statute of Great Poland, which went to the very root of the matter and greatly strengthened the hands of the king's justices. Casimir also did much for education. Stimulated by the example of Charles IV., who had founded the university of Prague in 1348, Casimir on the 12th of May 1364 established and richly endowed the first university of Cracow, which had five professors of Roman law, three of Canon law, two of physics, and one master of arts. The security of the kingdom was sensibly promoted by the erection of a cordon of fortresses on its north-eastern borders, and a blow was given to foreign interference when Casimir succeeded in gaining dominant influence over the independent Polish principality of Masovia, which had hitherto gravitated between Bohemia and the Teutonic Order.
Casimir's last political act was the conclusion of a fresh alliance with Louis of Hungary against Charles IV. at Buda in 1369. He died on the 5th of November 1370 from the effects of an injury received while hunting. Though married three times Casimir left no sons; but he had the satisfaction of knowing that his domains would pass into the hands of a nephew every whit as capable and sagacious as himself.
See Jan Leniek, The Congress of Visegrád (Pol.), (Lemberg, 1884); J.K. Kochanowski, Casimir the Great (Pol.), (Warsaw, 1900); Kazimierz J. Gorzycki, The Annexation of Red Russia by Casimir the Great (Pol.), (Lemberg, 1889); Stanislaw Kryzanowski, The Embassy of Casimir the Great to Avignon (Pol.), (Cracow, 1900).
(R. N. B.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)