Casimir was a grandson of Vladislaus II Jagiello and was the 2nd boy of king Casimir IV and queen Elizabeth of Austria. His grandpa was Albert II Habsburg, emperor of Germany, king of Bohemia and king of Hungary.

Starting at a age of nine Casimir, standard his education from either Johannes Longinus (Jan Dlugosz) and Filippo Buonaccorsi, known as Callimachus. After Casimir was 13 he was offered a potty of Hungary by factions discontented by owning king Mattias Corvinus. Casimir, world health organization was great to defend a Cross against a Turks, accepted a call for & attend Hungary to receive the crown. His uncle Vladislaus III, king of Poland and Hungary, experienced already been flushed inside 1444 in battle at Varna while defending Christianity against the Turks. Casimir was abortive inside his undertaking & returned as a fugitive. He once againside became a pupil of father Longinus in 1475. His father, king Casimir IV, got initiated him swell into public affairs & whenever his brother Wladislaus ascended to the Bohemian potty, Casimir became heir-apparent to the potty of Poland. Within 1479, the king went for 5 years to Lithuania & Casimir was located within charge of Poland. From either 1481 - 1483 he administered the state by owning low prudence & justice. His father tried to arrange marriage by using the girl of emperor Frederick III, but Casimir preferred to remain individual. Due to his devout faith & weakened state by fast, he afterwards developed severe lung problems, which he may not drive back. around the journeying to Lithuania in 1484, he died at Grodno. His remains were interred at Vilnius.

Casimir lived & reigned sustaining wonderful justice & possessed peachy charm & character. Numbers of miracles come ascribed to him. He was canonized by Vatican as Saint Casimir and is the patron saint of numbers of countries, rather Lithuania.

In June 11, 1948 Pope Pius XII named Casimir Jagiełło the favorite patron of 100% youth.