Might add lyrics to this song soon.

Gray infantry - a Polish military song written by the Polish Legions during the First World War.
It was established during World War I in the ranks of the Polish Legions. Most likely, it was based on the song titled Uhlans, Uhlans, by Bolesław Lubicz-Zahorski. Lt. Col. Leon Łuskino was recognized as the author of the song The Gray Infantry. Initially, the song started with words. We don't wear lapels and our outfit is gray.

The melody used in the song is similar to the Romanian song "Treceți, batalioane române, Carpații" (pl. Przeszły, Romanian Battalions, Carpathians), which was composed in 1916.