(Photo: Birgit Gufler) In 1874 Mussorgsky’s ‘Boris Godunov’ received its premiere at St. Petersburg’s Mariinsky Theatre. Yet, he was not the first to write an opera of that name, 164 years earlier in 1710 Johann Mattheson completed his version of “Boris Goudenow,” but for reasons which are now unclear it was not performed during the composer’s lifetime, and ended up {…}