FOOTNOTES. 1  1. Harold Mattingly, Coins of the Roman Empire in the British Museum, Vol. 2  3. Sutherland, C. H. V., The Roman Imperial Coinage Volume 1. (Spink & Son Ltd., London: 1984) pp. 27-29. 3  4. Kraay, C. M., The Behavior of Early Imperial Countermarks plate VI.