Vygantas (baptized Alexander; Polish: Wigunt; died June 28, 1392) was Duke of Kernavė. He was one of the sons of Algirdas, Grand Duke of Lithuania (1345–1377), and his second wife Uliana Alexandrovna of Tver.
In 1385 Vygantas supported his older brother Jogaila by signing the Union of Krewo. In 1386 he was baptized as Alexander and married with Hedwig, daughter of Władysław Opolczyk, in 1390. Polish nobles expected that Władysław would grant Vygantas the Dobrzyń Land, contested territory between Poland and the Teutonic Knights, as his dowry. Vygantas received Kuyavia from Jogaila instead. In 1388 he supported Poland in an armed conflict with the Teutonic Knights. He also supported Jogaila in the Lithuanian Civil War (1389–1392) against Vytautas the Great. Vygantas was considered as a replacement for unpopular Skirgaila as Grand Duke of Lithuania. However, he soon died. The rumors had it that he was poisoned – either by Vytautas or Skirgaila. He is buried in Vilnius Cathedral together with his brother Karigaila, who died in the civil war in 1390.
Vygantas should not be confused with his brother Andrei of Polotsk, who is sometimes referred to as Wigunt-Andrei following confused 15th-century chronicles of Jan Długosz. Kazimierz Stadnicki in his work Bracia Władysława-Jagiełły Olgierdowicza (published in 1867) suggested that Vygantas and his elder brother Theodore were the same person, but this theory was rejected.
- Family of Algirdas – family tree of Vygantas
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- Urban, William (2006). Samogitian Crusade. Chicago: Lithuanian Research and Studies Center. p. 206. ISBN 0-929700-56-2.
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- (Lithuanian) Avižonis, Konstantinas (1953–1966). "Vygantas". Lietuvių enciklopedija. XXXIV. Boston, Massachusetts: Lietuvių enciklopedijos leidykla. p. 167. LCC 55020366.