Socialist Soviet Republic of Byelorussia
The Socialist Soviet Republic of Byelorussia (SSRB) was a short-lived soviet republic, that existed in the territory of Belarus from the end of December 1918 to the middle of February 1919, centered in Minsk. It was created in Belarusian regions of the Western Oblast, and was later merged into the Socialist Soviet Republic of Lithuania and Belorussia.
Source: Wikipedia — Socialist Soviet Republic of Byelorussia (CC BY-SA 4.0)