The eldest daughter of Simeon Ivanovich the Proud from his first marriage with Aygusta (Anastasia) was born no later than 1336 [1, p. 14]. The sources do not indicate the date of birth of the princess, but, as is often the case, there is a date of her marriage, which makes it possible to approximately establish the period of birth.
The marriage with the son of Prince Vasily Mikhailovich of Kashin, Mikhail, was another step in a complex political and diplomatic game. The rapprochement with Moscow of the Kashin prince took place against the background of the establishment of a relative political balance between Moscow and Lithuania, also achieved through marriage diplomacy. The relationship with the Moscow prince significantly strengthened the position of Vasily Mikhailovich, who, moreover, received a label in the Horde for the Tver reign.
The marriage of Mikhail and Vasilisa took place in 1349 [I, 192-193; II, cl. 60].
The only child known to sources was Vasily, who in the future would also become the Prince of Kashin [2, p. 481].
Vasilisa Simeonovna died on April 20, 1369.
I. PSRL. T. X. Letopisnyi sbornik, imenuemyi Patriarshei ili Nikonovskoi letopis'iu (1177–1362 gg.). M., 2000.
II. PSRL. T. XV. Rogozhskii Letopisets. Tverskoi sbornik. M., 2000.
1. Kuchkin V.A. Moskovskie Riurikovichi (genealogiia, demografiia) // Istoricheskii vestnik, 2013. № 04 (151). S. 6–73.
2. Ekzempliarskii A.V. Velikie i udel'nye kniaz'ia severnoi Rusi v tatarskii period s 1238 g. po 1505 g.: biograficheskie ocherki po pervoistochnikam i glavneishim posobiiam. T. 2. Vladetel'nye kniaz'ia Vladimirskikh i Moskovskikh udelov i velikie i udel'nye vladetel'nye kniaz'iakh Suzdal'sko-Nizhegorodskie, Tverskie. Riazanskie. SPb., 1891.