Many of his works were inspired by Russian history, Russian folklore, and other national themes. Such works include the opera Boris Godunov, the orchestral tone poem Night on Bald Mountain and the piano suite Pictures at an Exhibition.
For many years Mussorgsky's works were mainly known in versions revised or completed by other composers. Many of his most important compositions have posthumously come into their own in their original forms, and some of the original scores are now also available.
The spelling and pronunciation of the composer's name has caused some confusion.
The family name derives from a 15th- or 16th-century ancestor, Roman Vasilyevich Monastyryov, who appears in the Velvet Book, the 17th-century genealogy of Russian boyars. Roman Vasilyevich bore the nickname "Musorga", and was the grandfather of the first Mussorgsky. The composer could trace his lineage to Rurik, the legendary 9th-century founder of the Russian state.
In Mussorgsky family documents the spelling of the name varies: "Musarskiy", "Muserskiy", "Muserskoy", "Musirskoy", "Musorskiy", and "Musurskiy". The baptismal record gives the composer's name as "Muserskiy".