Antoninus Pius (138-161) and Marcus Aurelius Caesar. AR Denarius, Rome mint, 141-143 AD. Obv. ANTONINVS AVG PI-VS P P TR P COS III. Laureate head of Antoninus Pius right. Rev. AVRELIVS CAESAR AVG PII F COS. Bare head of Marcus Aurelius right. RIC III 417a; C. 15. 3.24 g. 18.50 mm. Sound metal. An attractive example, well centred, brilliant and prettily toned. Very light graffiti or cleaning marks on reverse and some dark deposits on legends. Good VF. This dynastic denarius depicting Antoninus Pius and Marcus Aurelius illustrates the adoptive system of succession employed by emperors from Hadrian through Antoninus Pius as a means of ensuring a smooth transition of power to individuals prepared for rule. Dynastic succession through bloodlines tended to provide inexperienced leadership and could lead to civil war. While the system worked well for the so-called Adoptive Emperors, it should be noted that Nerva, Trajan, Hadrian, and Antoninus Pius all lacked sons that survived into adulthood, so the principle that adoption of the 'best man' should prevail over blood descent was never truly tested. In any case, it fell apart under Marcus Aurelius when he left the empire to his own son, the unstable Commodus. Diocletian (AD 284-305) took another stab at setting up a system of imperial succession absent blood descent, but it, too, broke down when two of his chosen colleagues favored their own natural sons. (Heritage 3012, 2011, 24695 note).