Salviati made a total of 800 square feet of mosaics for the portal and apse of the cathedral in 1894, modeled after cartoons by Professor Martin and Friz Geiges.
Mosaic tympanum of the Annunciation above the entry portal
Detail of the apse mosaic featuring Christ Enthroned, which is based on a depiction in Hagia Sophia and also reminiscent of the one in St. Mark's Basilica. The latter also served as the model for the portrait in St. Augustine's College, Canterbury.
Barr, Sheldon. Venetian Glass Mosaics: 1860-1917. London: Antique Collectors' Club, 2008. 127.
Sacred Destinations: Bonn Munster
Hans Weingartz on Wikimedia Commons
Erke's flickr Photostream
jaime.silva's flickr Photostream
Brian J. McMorrow on pBase