Question: What is the name of the Grand Duke of Lithuania, then the King of Poland, who reserved the rights of the overlord under the Pact of Vilnius and Radom?
Sentence (from "Pact 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.
Relevant evidence: Yes