Although its official name is Praça de D. Pedro IV, this square is known by locals as Rossio. A site where important historical events have taken place, since medieval times it has been considered the heart of Lisbon. Around 1450, Paço dos Estaus was built on the northern side of the square, on the grounds of the existing theatre. The palace was originally used for hosting foreign dignitaries. It then became a seat of the Inquisition, and, as a result, Rossio was for many years a place of public executions. Its current look is largely due to its renovations planned by the Marquise of Pombal after the earthquake of 1755, coordinated by architects Eugénio dos Santos and Carlos Mardel. Its splendid pavement, a typical Portuguese mosaic, dates from the 19th century. A statue of King Pedro IV stands atop the central column, built in 1874, giving the square its official name.