Marcus Aurelius Numerius Numerianus ruled together with his brother Carinus. They were sons of Carus, a Gaul raised to the office of praetorian prefect under Emperor Probus in 282 AD. In 282, the legions of the upper Danube in Raetia and Noricum proclaimed Numerian's father, the praetorian prefect Marcus Aurelius Carus, emperor, beginning a rebellion against the emperor Probus. Probus' army, stationed in Sirmium (Sremska Mitrovica, Serbia), decided they did not wish to fight Carus, and assassinated Probus instead. Carus, already sixty, wished to establish a dynasty; and immediately elevated Carinus and Numerian to the rank of Caesar. Carus' death left Numerian and Carinus as the new Augusti.

Main Roman Coin Book and Other References:

RIC = Mattingly, Harold    The Roman Imperial Coinage
BMC = Coins of the Roman Empire in the British Museum
RSC = Seaby, H A    Roman Silver Coinage
RCV = Sear, David R    Roman Coins and Their Values
Cr = Crawford, Michael    The Roman Republican Coinage
SB = Sear, David R    Byzantine Coins and Their Values
S = Coins of England and the United Kingdom
WW = Wildwinds.com (reference & attribution site)