Complex sentence: The republic was short-lived: in December 1918 Minsk was taken over by the Red Army and in January 1919 Minsk was proclaimed the capital of Byelorussian SSR.
Split into simpler sentences: The republic was short-lived: in December 1918 Minsk was taken over by the Red Army. In January 1919 Minsk was proclaimed the capital of Byelorussian SSR.