Nerva became emperor in 96 CE after a period of political instability. He did not have a biological son to inherit the throne. Roman law allowed an adoption to create a bond as strong as kinship between two men. Nerva chose Trajan, a popular military leader, as his adopted heir. This decision helped reconcile tensions between the army and the senate. The practice was not new to Rome. Augustus had adopted Tiberius centuries earlier. Claudius had adopted Nero before him. Julius Caesar had adopted Gaius Octavius, who later took the name Augustus. These adoptions ensured continuity when no direct bloodline existed.
Five Good Emperors Era
The first five rulers from 96 CE to 180 are known as the Five Good Emperors. Niccolò Machiavelli reviewed these leaders in Book 1, Chapter 10 of The Discourses on Livy. Edward Gibbon wrote in The History of the Decline and Fall of the Roman Empire that their rule showed wisdom and virtue. They governed with moderate policies unlike their more tyrannical successors. Hadrian died in 138 after a long reign dedicated to cultural unification. Antoninus Pius succeeded him under a condition to adopt Marcus Aurelius and Lucius Verus. Antoninus began a peaceful reign and shared power with the Senate. He adhered strictly to Roman traditions and institutions. His governance style set a standard for benevolent monarchy during this period.Trajan And Hadrian Strategy
Trajan expanded the empire's borders significantly during his reign from 98 to 117. He was Nerva's adopted heir and a respected military commander. After Trajan's death, Hadrian became emperor in 117. Hadrian claimed he had been adopted by Trajan on his deathbed. He shifted focus from expansion to defensive consolidation. Hadrian built fortifications along the northern frontiers to secure the empire. This strategy contrasted sharply with Trajan's aggressive territorial gains. Hadrian traveled extensively across the provinces to oversee these defenses personally. His approach stabilized the empire after years of constant campaigning. The transition between these two leaders marked a turning point in imperial policy.