The article is devoted to the military history research of Vilnius and Lithuanian rudiments of the Polish 13th Lancers Regiment. At the end of 1918 the situation with the former Grand Duchy of Lithuania was complicated as the German Army had left this area and the Red Army wanted to take it over. It is worth noticing that Polish society was willing to organize military self-defence to protect themselves from Bolshevik attacks. The most important moment of forming the Polish units was at the end of December 1918 at Pośpieszka estate where the 1st Lancers Regiment of Vilnius was formed. Then it fought the Bolsheviks at the end of 1918 and in January 1919. This way the new page of Polish military history was opened.