The published manuscript is related to the history of the most significant work of Dimitar and Konstantin Miladinov – their collection Bulgarian Folk Songs. The manuscript is preserved in the archive of the Russian Slavicist Izmail Sreznevsky. At the end of 1858, Konstantin Miladinov compiled a representative collection written in Cyrillic for the St. Petersburg Archaeological Society, of which Sreznevsky was a member. His desire was to show the diversity of the entire collection, but the emphasis is on heroic songs (514 of 830 verses). Konstantin Miladinov's notes on the songs are of great interest. There are 215 of them and they contain: Russian translations of a number of words, Turkish translations of words, comparisons between the Macedonian and Eastern Bulgarian dialects. The notes testify to the serious philological training received by Konstantin Miladinov, both in Greece and in Russia.