"The atelier which executed the mosaics of St. Mary's of the Admiral was a separate entity distinct from that which was operating during the same period in the sanctuary of the Capella Palatina  .  .  . The atelier must have been procured from a metropolitan Byzantine milieu  .  .  . presumably all imported from Constantinople" (852 miles as the crow flies).

 Ernst Kitzinger, The Mosaics of St. Mary's of the Admiral in Palermo (Dumbarton Oaks Studies 27; Washington, D.C. 1990)