The First Polish Corps was formed in the North-Western region of Russia in the summer of 1917 for subsequent deployment to the front. General Dowbor-Musnitski was appointed commander of the corps. Due to changes in the situation at the front and within Russia, the corps was not sent to the front. In early 1918, the Polish Corps refused to submit to the Soviet government and began taking part in combat operations against the Red Guard in Belarus. In May 1918, the corps was disarmed and disbanded, and its remaining troops were withdrawn to Poland.
In March 1918, by order of Dowbor-Musnitski, overprints were applied to Russian Empire stamps featuring the Polish coat of arms and the inscription: "Poczta Pol. Korp." (Post of the Polish Corps) — the first issue.
The second issue was produced somewhat later with a modified overprint of the coat-of-arms design and the inscription: "Pol. Korp." (without "poczta") and a new value at the bottom of the stamp.