Trinity Cathedral (Troitsky Sobor) is the oldest building of the Lavra, it dates from the 15th century. It is open during religious services. The sacristy is the only part belonging to Lavra and a part of the city museum. The construction of the cathedral became possible thanks to donations of Vasily II Tyomniy (Blind), the Grand Prince of Moscow Vasily Dmitriyevich and his younger brother Yuriy Dmitriyevich. Besides, in the cathedral there is the tomb of Boris Godunov.