Complex sentence: In 1918 he organized the Lithuanian and Belarusian Self-Defence and 1st Lithuanian-Belarusian Division and on 8 December he was officialy accepted into the newly forming Polish Army by the order of Józef Piłsudski in the rank of major general.
Split into simpler sentences: In 1918 he organized the Lithuanian and Belarusian Self-Defence force and the 1st Lithuanian-Belarusian Division. On 8 December, he was officially accepted into the newly forming Polish Army by the order of Józef Piłsudski at the rank of major general.