Claudius. AD 41-54. Æ Sestertius. Rare countermark.

Claudius. AD 41-54. Æ Sestertius 35 mm. 24.6 gm. Rome mint. Struck AD 41-42. Obv: TI CLAVDIVS CAESAR AVG PM TRP IMP, Laureate head right; c/m: ROB- in incuse rectangle. Rev: EX S C/P • P/OB CIVES/SERVATOS in four lines within oak wreath. RIC I 96; von Kaenel Type 54; for c/m: Pangerl 23, note 150; BN 131. Tiber Patina. A very rare variety of the common PROB(atum) countermark. (see C. Kraay, “The Behaviour of Early Imperial Countermarks,” Essays Mattingly, pp. 130-131). This variety does not appear to be caused by a broken or filled die, but was engraved ROB, with perhaps the P being understood as ligate with the R. The extended crossbar of the B is also unique to this variety. These countermarks may have been applied in Britain, following the time of the Boudicca revolt.