On this day, in 1791, was proclaimed....

On this day, in 1791, was proclaimed the Constitution of the Polish–Lithuanian Commonwealth, the first constitution in Europe.

The arms of the Polish–Lithuanian Commonwealth quartered the arms of Poland and Lithuania and the usual additaments of an European Continental king.

https://commons.wikimedia.org/wiki/File:Coat_of_Arms_of_the_Polish-Lithuanian_Commonwealth.svg#/media/File:Coat_of_Arms_of_the_Polish-Lithuanian_Commonwealth.svg

File:Coat of Arms of the Polish-Lithuanian Commonwealth.svg - Wikimedia Commons