Domitian’s murder marked the end of the Flavian dynasty and changed the rules of succession. Nerva and Trajan (ruled 96 – 98 AD, 98 – 117 AD) were not born to rule, but were chosen for the job.

For most of this period, emperors were not chosen on the basis of their ability or honesty, but simply because they were born in the right family ... while Nerva "adopted" Trajan to ensure ...