Empress Theodora and court mosaic Italy

Empress Theodora (byzantine empress, wife of Justinian) and court fra,ed

This is marked on the back with an aged label that reads "The Empress Theodora and her court", as well as "MOSAICO DEL VI SEC. M.P. 804"...it is very worn and I may have not gotten some of the letters correctly. It is also stamped MADE IN ITALY. It is in a simple gold frame that is very worn but looks as if it might have been retouched a bit. It measures about 12 1/2" x 16 1/2". It's a bit heavy and looks almost like stone with the images imprinted on it...never saw this type of item or medium before. Can't find any info except the historical background and some tapestries. She was a Byzantine Empress married to Justinian and the original mosaic which is more colorful and detailed is in the Basilica at San Vitale, Italy. She seemed to be quite controversial and influential in her era. The picture itself seems to be in very good condition and details are intact. The back is an enigma as well and seems to be a brown paper bag color and looks like pieces of parchment or something pieced together. Any info you can give me as to what this is or its worth would be greatly appreciated. I purchased it in a little shop that couldn't provide me with any info on it whatsoever. I have never seen an Italian mosaic so I don't know if this is a print on a stonelike board or what...it does say "Mosaico" and "made in Italy" on back but I am stumped...I would like to resell it at some point. Thanks for any help you can give me.