Pact of Vilnius and Radom

Vytautas, Grand Duke of Lithuania, became fully in charge of the Lithuanian affairs, while Władysław II Jagiełło, King of Poland, reserved the rights of an overlord.

[3] The same year Vytautas suffered a major defeat in the Battle of the Vorskla River against the Golden Horde[4] and faced rebellions in the Principality of Smolensk, Republic of Pskov, and Velikiy Novgorod.

The union was signed in three separate acts: one by Władysław II Jagiełło (the original of which did not survive), another by Vytautas and the Lithuanian nobles (in Vilnius on 18 January 1401), and the third by the Polish Royal Council (in Radom on 11 March 1401).

[6] At the time neither Władysław II Jagiełło nor Vytautas had heirs, but each hoped to sire legitimate sons that would inherit both the Kingdom of Poland and the Grand Duchy (eventually it would be Jogaila who would succeed in this).

[8] The renewed alliance stabilized the situation, allowing Vytautas to launch an offensive against the Teutonic Knights and to initiate the first Samogitian uprising.