The daughter of the Grand Duke of Lithuania Algirdas and Juliana of Tver, Alexandra was born in the late 1360s. [2, p. 306]. Since the exact date of her birth is unknown, it is impossible to reliably determine the seniority of the princess among her brothers and sisters.
In 1387 her elder brother Jagailo, who had been crowned a year before as Vladislaus II, gave Alexandra to the Masovian prince Siemovit IV as a wife [4, p. 64-66]. In the face of a constant struggle for power, Alexandra's marriage removed one problem from Jagiello-Vladislaus: Siemovit, as a representative of the Piast House, could lay claim to the Polish throne [1, p. 57-82]. In exchange for the principality of Belsk and 10,000 grosz paid as a dowry, Siemovit renounced his claims to the Polish throne [5, p. 7; 6, s. 76-81].
In marriage Alexandra had 12 (according to other sources - 13) children [2, p. 306; 3, p. 904; 4, p. 64-66].
Alexandra died on April 20 / June 19, 1434 in Plock. She was buried in the Plock Cathedral.
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Gudavičius E.Aleksandra // Antanas Račis (ed.). Visuotinė lietuvių enciklopedija. Vilnius, 2001.
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Piotrowicz K.Aleksandra // Polski Słownik Biograficzny. T. 1. Kraków, 1935. P. 66–67.
Stone D. The Polish–Lithuanian State, 1386–1795. A History of East Central Europe. University of Washington Press, 2001.
Supruniuk A. Siemowit IV // Polski Słownik Biograficzny. T. XXXVII/1, zeszyt 152. Warszawa–Kraków, 1996. S. 76–81.