Born in 1310, Casimir found himself in a fragmented kingdom that was in shambles, underpopulated and nearly ruined by three successive Mongol invasions. Upon his coronation in 1333, he immediately rolled up his sleeves and began to leave his indelible mark on Poland. In 1334, King Casimir reaffirmed privileges granted to Jewish Poles by King Boleslaw IV in 1264. Additionally, he declared them to be "a people of the king" and created new laws to further protect them. He then invited Jews from elsewhere in Europe, who were persecuted and blamed for the plagues, to join him in his Kingdom of Poland. Today, about 70% of Ashkenazi, European Jewry, have their ancestral roots in Poland due to the benevolence of Casimir III. He also invited Saxons, Moravians, Dutchmen, and others to emigrate and become pioneers in the resettlement of the kingdom. Hundreds of towns received their official town charters from King Casimir III. Based upon the destruction that he viewed from the Mongol Invasions, whenever he undertook public works projects, he insisted on the use of brick and stone. He wanted his kingdom to safely endure all perils for generations to come. This is the basis for the famous Polish saying regarding King Casimir III: "Zastal Polske drewniana a zostawil murowana" - "He found a Poland made of wood and left it made of stone". During his reign, the territory of Poland more than doubled in size. With four wives, several mistresses, and countless other likely liaisons, King Casimir III might be called "the father of his country" in jest.He reorganized government and promulgated new civil and commercial laws. He laid the foundation for the Poland that was yet to come. Casimir III, Casimir the Great, Kazimierz Wielki, the Peasant's King died in 1370 naming his nephew, King Louis I of Hungary, as his successor. But a real prosperity would not begin until Jadwiga, daughter of Casimir's nephew, ascended to the Polish throne. With the Union of Krewo, Poles and Lithuanians finally had the opportunity to develop their economies and a lucrative agricultural export market that became the foundation for Poland's wealth and prosperity.