The Western Division was formed in August 1918 in the area of Moscow and Tambov at the initiative of Social Democracy of the Kingdom of Poland and Lithuania (SDKPiL) and the Polish Socialist Party-Left (PPS-Lewica), part of the Moscow Military District. A Polish communist regiment, the "Red Regiment of Revolutionary Warsaw" (Czerwony Pułk Rewolucyjnej Warszawy) made up its cadre, and in the beginning it was mostly composed of Polish volunteers. According to its order of battle (below) each of its brigades consisted of two battalions of infantry and one battalion of cavalry.