Constantine V and Pope Zacharias. AR 1/8 Siliqua. 

AR Eighth of Siliqua Obv: Crowned beardless facing bust, wearing chlamys; cross in left field.

Rev: Rm monogram; Z (Zacharias) in upper left field. [This 
class was unknown before 1985 and is of considerable 
interest. Its existence shows that the silver coins at 
present listed in the various standard works under 
Constantine V for Rome, those with the reverse type K 
combined with a cross and emperor wearing a loros, must be 
re-attributed to Pope Constantine. Zacharias is also known 
to have issued square bronze tessere, cf. Berman pg. 31, 5. 
Pope (and St.) Zacharias is noteworthy in history for his 
momentous decision to bless St. Boniface's anointment of 
Pepin the Short as king of the Franks. In 751, Zacharias 
appealed for the Franks' help against Aistulf, who had taken 
Ravenna and was demanding suzerainty over Rome as part of 
his enlarged dominion of the Lombards. CNG]. 741-752 (Rome). 
$2,000 5/22/02.

SB 1579, Berman 4 

Used by permission of Classical Numismatic Group, www.cngcoins.com.