Historic records suggest that in the 16th c. Lithuanian noblemen resided here during the proceedings of the Sejm debating on the signing of the Polish-Lithuanian Union in 1569. This significant event is commemorated with a monument shaped like an obelisk. In the square there are also monuments to the Unknown Soldier, the Constitution of May 3rd 1791, and to Marshal Józef Piłsudski. Buildings situated by the northern side of the square used to be palaces owned by the Czartoryski Family, the Lubomirski Family or the Governorate authorities after the partitions of Poland. Opposite there is an impressive edifice of the Main Post Office in Lublin, which owes its present look to a reconstruction from 1921.