This is the second-oldest church in Vienna, and the spot on which it stands could well be Vienna's oldest Christian church site. It's believed that a place of worship stood here in the second half of the 4th century. Charlemagne is credited with having founded a church on the site during the late 8th or early 9th century.
The present St. Peter's is the most lavishly decorated baroque church in Vienna. Gabriel Montani designed it in 1702. Hildebrandt, the noted architect of the Belvedere Palace, is believed to have finished the building in 1732. The fresco in the dome is a masterpiece by J. M. Rottmayr depicting the coronation of the Virgin. The church contains many frescoes and much gilded carved wood, plus altarpieces done by well-known artists of the period.