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.