St. Casmir is the patron saint of Poland and Lithuania. His feastday is on March 4th.  
He was born on October 3, 1460, in the  palace at Cracow in Poland and was the son of King Casimir IV and Elizabeth of Austria, Poland. He was shown to be religious when very young and refused to do things that he thought were not fair. He was left in charge of Poland when his father was away and ruled very fairly. He died in 4th March  1484. His tomb became famous for miracles and he became a saint  in 1522.