Otto Wagner enlisted many artists and artisans who were part of Vienna's Secessionist movement to help decorate the building.
The painter and stage designer Remigius Geyling sketched the mosaics behind the main altar (1878-1974) which were then completed by Leopold Forstner (1878-1936). They represent the reception of the saints into heaven. The altar is highlighted by a lavishly ornate baldachin.


Otto Wagner Church or Steinhof Church, (Kirche am Steinhof) - also called the Church of St. Leopold, was built between 1903 and 1907 by the 63-year-old architect Otto Wagner.
It is considered one of the most important Art Nouveau churches in the world.