Succession is the final act of leadership. For as long as power has been concentrated in the hands of mortals, men and women have sought to ensure they are followed by their chosen heir – perhaps an oldest child or political protégé. But if you want to make god laugh, tell him your succession plans.
Once granted the full force of office and with authority consolidated, new leaders tend to have a mind of their own. The Roman Emperor Trajan adopted Hadrian as his successor in 117. After Trajan’s death, Hadrian swiftly abandoned his predecessor’s expansionist policies, pulling out of Parthia (modern-day Iran) and Dacia (Romania). Indeed, Hadrian went further still, building walls not so much to keep invaders out but to define the frontier of Rome’s power.
