The Polish-Lithuanian and Prussian Alliance was a mutual defense alliance signed on 29 March 1790 in Warsaw between representatives of the Polish–Lithuanian Commonwealth and the Kingdom of Prussia. It
3 May Constitution, by Matejko, 1891. King Stanisław August (left, in regal ermine-trimmed cloak), enters St. John's Cathedral, where Sejm deputies will swear to uphold the new Constitution. In background, Warsaw's Royal Castle, where the Constitution has just been adopted.