Union of Vilnius and Radom

The Pact of Vilnius and Radom (Polish: Unia wileńsko-radomska, Lithuanian: Vilniaus-Radomo sutartis) was a set of three acts passed in Vilnius, Grand Duchy of Lithuania, and confirmed by the Crown Council in Radom, Kingdom of Poland in 1401. The union amended the earlier act of the Union of Krewo (1385) and confirmed the Ostrów Agreement (1392). 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. After the death of Vytautas, Lithuania was to be ruled by Władysław II Jagiełło or his legal heir. The union is generally seen as strengthening of the Polish–Lithuanian union.

Both Władysław II Jagiełło, King of Poland, and Vytautas, Grand Duke of Lithuania, sought to renew the Polish–Lithuanian union, which had existed since 1385. In 1399, Queen Jadwiga of Poland died due to childbirth complications, leaving Władysław II Jagiełło king of a foreign land and without an heir. If Polish nobles forced Władysław II Jagiełło to abdicate the throne, he would return to Lithuania demanding the throne of the Grand Duke. Vytautas would be forced either to return to Duchy of Trakai or launch another civil war. The same year Vytautas suffered a major defeat in the Battle of the Vorskla River against the Golden Horde and faced rebellions in the Principality of Smolensk, Republic of Pskov, and Velikiy Novgorod.

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