There is no evidence of her existence in primary sources.Сперанский М. Н. Русские подделки рукописей в начале XIX в. — ПИ, 1956, т. V, с. 100 The first mention can be found in 19th-century Russian literature.Н. И. Костомаров, «Смутное время Московского государства в начале XVII столетия 1604—1613» // Вестник Европы, 1866 Nikolay Kostomarov in 1866 wrote that the notice about her was found by Afanasiy Byichkov in a manuscript in the Imperial Public Library.
