1st Lithuanian – Belarusian Division The 1st Lithuanian – Belarusian Division ( , ) was a volunteer unit of the Polish Army formed around December 1918 and January 1919 during the Polish – Soviet War . It was created out of several dozen smaller units of self - defence forces created out of local volunteers in what is now Lithuania and Belarus amidst a growing series of territory disputes between the Second Polish Republic , the Russian SFSR and several others local provisional governments and took part in several key battles of the war . History . Predecessors . With the end of the World War I , a growing series of territorial disputes between Poland , Soviet Russia and several other local provisional governments erupted in a series of wars in Central and Eastern Europe , the most prominent of these being the Polish – Soviet War . Starting in the last years of the First World War , many smaller units of self - defence forces were created out of local volunteers in those areas , among them likely the best known being the Lithuanian and Belarusian Self - Defence ( ' Samoobrona Litwy i Białorusi ' ) . Self - Defence units were organized in the areas of the Kresy region with Polish majorities or significant minorities – usually urbanized areas like the cities of Vilnius , Minsk , Hrodna , Lida and Kaunas , or towns like Ašmiany , Wilejka , Nemenčinė , Świr and Panevėžys ; until December 1918 those units had no central command or organization and many of them were named after the local cities or regions ( like ' Samoobrona Lidy ' ) . The first task of those units was curbing the crime wave by German deserter s , and later , defence from the pro - Bolshevik groups . Despite its name , most of the members of that organization were either Poles or polonized , and therefore supported the cause of attaching those territories with the newly recreated Polish state . Operational history . The initial core of the future division was formed in December 1918 in Minsk , where a group of roughly 1500 Poles and Belarusians rose to arms to defend the city against the advancing forces of Soviet Russia . However , due to Russian numerical superiority and lack of support from the side of the short - lived Belarusian National Republic , the group withdrew towards central Poland . Other such self - defence groups , resistance organizations and veterans of the Green Army of the Russian Civil War also reached Poland , where they were reformed into a single unit under the command of general Władysław Wejtko . Another large group of volunteers to join the division were the remnants of roughly 2 , 500 men strong force created in Vilnius to defend it against the Reds in January 1919 . In the effect of four - day - long fights for the city and the area of Nowa Wilejka , the Polish forces were pushed back and the city had to be abandoned . The newly formed division took part in the Battle of Brześć Litewski of January 8 of that year , one of the first battles of the Polish – Soviet War . The division , commanded by Gen . Jan Rządkowski , took part in many of the largest battles of that conflict . Among others , it played a major role in the Battle of Radzymin , a part of the Battle of Warsaw , the decisive struggle of the war . It also took part in the Battle of the Niemen , where it suffered heavy losses . Finally , two days prior to the cease fire ending the war , the units of the division – then commanded by Gen . Lucjan Żeligowski – took over Vilnius Region from the Lithuanian forces and formed the core of the armed forces of the Republic of Central Lithuania . Following the elections held there and that state ' s merger with Poland in 1923 , the division was partially demobilized , while its remnants were incorporated into the Polish 19th Infantry Division stationed in Vilnius ( Polish : " Wilno " ) .