Complex sentence: "Columbus Describing Third Voyage" was one of five designs engraved by Robert Savage, all of which were his sole work, engraved without collaboration with either of the other two engravers working on the Columbian Issue.
Split into simpler sentences: Columbus Describing Third Voyage was one of five designs engraved by Robert Savage. All of which were his sole work, engraved without collaboration with either of the other two engravers working on the Columbian Issue.