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 Crecy, 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