Aigusta was baptized as Anastasia in order to marry Simeon of Russia in 1333; he became Grand Prince of Moscow in 1341. There is no direct evidence that she was a daughter of Gediminas, but because the marriage was high-profile, most historians have concluded that she was a member of Gediminas' family. The marriage had great potential because Lithuania and Moscow were fierce rivals for supremacy in Ruthenia, but conflicts broke out again in 1335, just two years after the marriage. Her two sons Vasilei and Konstantin did not survive infancy; her daughter Vasilisa married Mikhail Vasilevich of Kashin, a Tverite prince opposing Lithuania. Her brother Jaunutis sought her help when he was deposed by Algirdas in 1345. Immediately before her death on 11 March 1345 Aigusta became a nun. She was buried within the Moscow Kremlin at a monastic church whose construction she had sponsored.