Pipkov began Momchil in the years after 1939, working with the poet Hristo Radevski on a libretto drawn from Stoyan Zagorchinov's novel of fourteenth-century Bulgaria. The opera reached the Sofia National Opera in 1948, conducted by Assen Naydenov and staged by Mihail Hadzhimishev. Its subject is the warlord Momchil, holding his people between Byzantium and the advancing Ottomans — a story that carried a second meaning at the time it was written. Pipkov took his melodic material from village song and irregular Balkan metres rather than quoting folklore; the introduction and dances became independent concert items.