During restoration of the Dormition Cathedral (Успенский собор), restorers found hidden frescoes that no one has seen before. The Dormition Cathedral inside the Moscow Kremlin’s walls used to be the country’s main church until the 1917 Bolshevik Coup. Almost all Russian tsars were coronated and married there. In 1643, the first tsar of the Romanov dynasty, Mikhail I, ordered to paint the cathedral anew (заново), and the old frescoes were preserved until today. In 2018 restorers (реставраторы) found some frescoes that no one had seen before behind the altarpiece walls. There are low hidden parts of two compositions: ‘Cathedral of Our Lady’ (Собор Богоматери) and ‘Birth of John the Baptist’ (Рождество Иоанна Предтечи). Research shows that these wall paintings are most likely to be dated around 1481, when Dionisy and other masters made the iconostasis. If these conclusions are correct, it means it’s an absolutely unique discovery, as frescoes of Dionisy and his contemporaries have almost all been lost.
Look at the gallery of photos here