Built for Ferdinand Bonaventura, Count Harrach, from 1689, to plans drawn up by Domenico Martinelli, this palace was completed by Johann Lukas von Hildebrandt. In 1845, it was extensively altered by the removal of the pediment of the main façade and the remodelling of the courtyard. The building, hit during a bombardment in 1944, was rebuilt in the Baroque style.