The situation was further aggravated by the absence of a clear successor , made more pressing because of Nerva 's old age and sickness . He had no natural children of his own and only distant relatives , who were unsuited for political office . A successor would have to be chosen from among the governors or generals in the Empire and it appears that , by 97 , Nerva was considering to adopt Marcus Cornelius Nigrinus Curiatius Maternus , the powerful governor of Syria . This was covertly opposed by those who supported the more popular military commander Marcus Ulpius Traianus , commonly known as Trajan , a general of the armies at the German frontier .