[1] The square was built in 1821 at the site of the ruins of a medieval Capuchin monastery, which had been abolished during the reign of Habsburg Emperor Joseph II.

On October 29, 1918, independence from Austrian-Hungarian rule and the establishment of the State of Slovenes, Croats and Serbs was proclaimed during a mass demonstration on the square.

In May 1945, the Yugoslav Communist leader Josip Broz Tito first visited Slovenia after World War II and held a speech on the balcony of the University of Ljubljana, which faces the square.

On June 22, 1988, the first free mass demonstration was held on the square demanding the release of four Slovene journalists imprisoned by the Yugoslav army.

On June 21, he publicly addressed the crowd gathered on Congress Square, quoting the opening verses of the Slovenian national anthem.

The statue was removed by "patriots" in the night of the December 30, 1918, after the collapse of Austria-Hungary and the end of World War II, and later placed in the National Museum.

In 1954, after the formal annexation of Zone B of the Free Territory of Trieste to Yugoslavia, an anchor was placed in the park to symbolize victory over Italian expansionism and the union of the Slovenian Littoral with the rest of Slovenia.