Wladyslaw II Jagiello

Władysław II Jagiełło, as Grand Duke of Lithuania, signed the Union of Krewo with Poland, agreeing to convert Lithuania to Christianity and marry Queen Jadwiga of Poland. This personal union created the Polish-Lithuanian union and made Jagiełło King of Poland.

Władysław II Jagiełło oversaw the official Christianization of Lithuania, the last pagan state in Europe. He established the Diocese of Vilnius and promoted the Latin rite, integrating Lithuania into Western Christendom.

Władysław II Jagiełło led the combined Polish-Lithuanian forces to a decisive victory over the Teutonic Order at Grunwald. The battle broke the Order's military power and marked the zenith of Polish-Lithuanian strength in the region.

Władysław II Jagiełło signed the First Peace of Thorn with the Teutonic Order after Grunwald. The treaty granted Samogitia to Lithuania for Jagiełło's lifetime and required the Order to pay a large indemnity, but did not fully exploit the military victory.

Władysław II Jagiełło sent a Polish delegation to the Council of Constance, where they defended the rights of pagan Lithuanians against Teutonic accusations. The Polish representative Paweł Włodkowic argued for religious tolerance, influencing European legal thought.