It is believed that Caldesi was the photographer and that Montecchi was his business partner. Although not mentioned on the title page Robert Howlett is credited with twelve photographs in the Ancient Series and eighteen photographs in the Modern Series. This work was issued in parts and the plates carry the dates May 1857, Sept. 1857 and Dec. 1857. In the Ancient Series the engraved numbers on the plates (which indicate the sequence in which they appear in the Parts Publication) differs from those on the contents page where they are listed chronologically.