In what year was the mother of Karigaila born?
Uliana of Tver: Uliana Alexandrovna of Tver (Russian: Ульяна Александровна Тверская ;  1325 – 17 March 1391) was a daughter of Prince Alexander of Tver and Anastasia of Halych (daughter of Yuri I of Galicia).
i don't know