The term 'Boris Godunov Singers' refers to a group of bassi, or five-part male choirs, that perform the opera of the same name by Russian composer Modest Mussorgsky. The opera is based on the life of Tsar Boris Godunov and is considered one of the greatest works of Russian music. The bassi are an integral part of the performance, providing a powerful and dramatic accompaniment to the soloists and chorus.