Prince Archbishop Franz Anton von Harrach had the palace remodeled extensively from 1721 to 1727 by the famous Baroque architect, Lukas von Hildebrandt, who combined the individual parts of the building to form a homogeneous palace. The palace was heavily damaged by the disastrous town fire on April 30, 1818, destroying the frescoes painted by Johann Michael Rottmayr and Gaetano Fanti. Fortunately, the great marble staircase leading into the palace and the Marble Hall remained undamaged.

Peter de Nobile, court architect and director of the school of architecture in Vienna, gave the palace its present unassuming, neo-classical appearance. Details such as the scroll work around the windows, the chapiters and the stucco work are the reminders of its former splendor. The stairway by Lukas von Hildebrandt is one of the palace’s great masterpieces. White marble putti (cherubs) adorn the lavishly embellished marble balustrade; the figures in the niches are the work of the famous sculptor, Georg Raphael Donner (1726) and among the most beautiful creations of the European Baroque era.

Today the Marble Hall, formerly the prince archbishop’s banquet hall where Mozart’s father Leopold and his children Wolfgang and Nannerl once played their instruments, is acknowledged to be one of the “most beautiful wedding halls in the world". The Marble Hall also serves as an elegant venue for conferences, awards ceremonies and exquisite concerts (Salzburg Palace Concerts).