The main altar, completely separated from the rest of the church, is highlighted by a lavishly ornate baldachin.
The elaborate and brightly coloured mosaic behind the ornate altar represents the reception of the saints into heaven.
Among the numerous saints attending the ceremony is Saint Dymphna the patron saint of those afflicted by epilepsy or mental illness. Also visible is St. Clement Hofbauer or Clemens Maria Hofbauer, the patron saint of Vienna.
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).