The Jagiellon Dynasty was a royal family that ruled over several Central and Eastern European countries from the late 14th to the 16th centuries. It originated with Jogaila, the Grand Duke of Lithuania, who became King of Poland in 1386 through his marriage to Queen Jadwiga. The dynasty played a significant role in the political landscape of Europe, uniting Poland and Lithuania. The Jagiellons expanded their influence through strategic marriages and alliances, leading to a powerful state known as the Polish-Lithuanian Commonwealth. Notable rulers included Casimir IV and Sigismund I, who contributed to cultural and economic growth. The dynasty ended in 1572 with the death of Sigismund II.