This is the principal public square of Intramuros. It was historically known as the Plaza Mayor. It was converted into a garden in 1797. In 1901, it was renamed Plaza McKinley in honor of US President William McKinley.

During the Second World War, it was renamed by the Japanese sponsored Philippine Government as Plaza Malaki.

The name reverted to Plaza McKinley after the war. The square was renamed Plaza Roma in honor of the College of Cardinals in Rome after the elevation of Archbishop Rufino Santos of Manila as the first Filipino cardinal in 1960.

In the square is a monument to Charles IV, King of Spain (1788-1808). The monument was put up in gratitude of his decree to introduce the smallpox vaccine in the Philippines.

It was cast in bronze under Governor General Rafael Maria Aguilar and upon the direction of Ambrosio Casas, 1805-1808. The monument was unveiled in 1824.

The statue was replaced with a monument to the martyr priests Gomez, Burgos, and Zamora (GomBurZa) in 1961.

The Charles IV monument was reinstated under the Intramuros Administration. In 2016, it was declared a National Cultural Treasure.