Did Belarus adopt its first Constitution in the Soviet Union?
The first constitution in the Belarusian land was the constitution of May 3 1791, adopted by the Polish-Lithuanian Commonwealth, which comprised Belarus, in order to redress the political defects of the state and to enable it to withstand the hostilities of its neighbours, Russia, Austria and Prussia. It was Europe’s first, and the world’s second, modern codified national constitution, after the 1788 constitution of the United States. The constitution introduced political equality between townspeople and nobility and sought to establish a more democratic constitutional monarchy. The constitution was in effect for only a year, until the Russo-Polish War of 1792.
https://belarusdigest.com/story/myths/did-belarus-adopt-its-first-constitution-in-the-soviet-union/