Question: Vykintas was a rival to which first Grand Duke of Lithuania?
Sentence (from "Mindaugas"): Mindaugas (German: "Myndowen" , Latin: "Mindowe" , Old East Slavic: Мендог — "Mendog" , Belarusian: Міндоўг or Mindoūh , c. 1203 – autumn 1263) was the first known Grand Duke of Lithuania and the only King of Lithuania.
Relevant evidence: Yes