Constantine IV Pogonatus, 668-685 with Pope St. Benedict II. Eighth Siliqua or 30 Nummi (Silver, 8.04 mm, 0.15 g), Rome, circa 684-685. Bust facing, wearing crown and chlamys, holding globus cruciger. Rev. Rm in monogram, combined with a short barred cross monogram; in upper left field, eight-pointed star. DO 80b. MIB 74. Sear 1233. M. D. O´Hara - I. Vecchi, A Find of Byzantine Silver from the Mint of Rome for the Period A.D. 641-752, Schweizer Numismatische Rundschau (Revue Suisse de Numismatique) 64, 1985, 11-13. Toned, with minor deposit. About Extremely Fine. Extremely Rare.
This extremely rare small silver coin strikingly combines the portrait of the Byzantine emperor on the obverse with the monogram of the bishop of Rome (the Pope) on the reverse, suggesting that the popes may have exercised temporal authority far earlier than historians have traditionally assumed.