He reformed the judicial system and introduced several undying codified statutes, gaining the title "the Polish Justinian".

He also confirmed privileges and protections previously granted to Jews and encouraged them to settle in Poland in great numbers.

[4] When Casimir attained the throne in 1333, his position was in danger, as his neighbours did not recognise his title and instead called him "king of Kraków".

These achievements are still celebrated today, in a commonly-known ditty that translates as follows: inherited wooden towns and left them fortified with stone and brick (Kazimierz Wielki zastał Polskę drewnianą, a zostawił murowaną).

[7] Casimir is the only king in Polish history to both receive and retain the title of "Great", as Bolesław I is more commonly known as "the Brave".

He conquered the Ruthenian kingdom of Halych and Volodymyr (a territory in the modern-day Ukraine), known in Polish history as Red Ruthenia and Volhynia.

By extending the borders far south-east, the Polish kingdom gained access to the lucrative Black Sea trade.

In exchange Casimir gained a favourable Hungarian attitude, needed in disputes with the hostile Teutonic Order and the Kingdom of Bohemia.

This part of the testament was invalidated by Louis I of Hungary, however, who had traveled to Kraków quickly after Casimir died (in 1370) and bribed the nobles with future privileges.

He introduced the codes of law of Greater and Lesser Poland as an attempt to end the overwhelming superiority of the nobility.

During his reign all three major classes — the nobility, priesthood, and bourgeoisie — were more or less counterbalanced, allowing Casimir to strengthen his monarchic position.

He reportedly even supported a peasant whose house had been demolished by his own mistress, after she had ordered it to be pulled down because it disturbed her enjoyment of the beautiful landscape.

[citation needed] His popularity with the peasants helped to rebuild the country, as part of the reconstruction program was funded by a land tax paid by the lower social class.

[20] After Casimir "divorced" Adelaide he married his mistress Christina Rokiczana, the widow of Miklusz Rokiczani, a wealthy merchant.

The title in Latin was: Kazimirus, Dei gratia rex Polonie et Russie, nec non Cracovie, Sandomirie, Siradie, Lancicie, Cuiavie, et Pomeranieque Terrarum et Ducatuum Dominus et Heres.