Jadwiga of Poland
In 1385, the Union of Krewo was signed between Queen Jadwiga of Poland and Jogaila, the Grand Duke of Lithuania, the ruler of the last pagan state in Europe. The act arranged for Jogaila's baptism and the couple's marriage, which established the beginning of the Polish–Lithuanian union. After Jogaila's baptism, he was known in Poland by his baptismal name Władysław and the Polish version of his Lithuanian name, Jagiełło. The union strengthened both nations in their shared opposition to the Teutonic Knights and the growing threat of the Grand Duchy of Moscow.