Caligula and Agrippina I, AV aureus, Rome, 40 AD.

C CAESAR AVG PON M TR POT III COS III, laureate head right.
AGRIPPINA MAT C CAES AVG GERM, draped bust of Agrippina I right.

RIC 21 (Caligula); Cohen 5; BMC 22

With permission of numislanz.de, Auktion 102, lot 473