It is commonly believed that the reign of Nerva, Trajan, Hadrian, Antoninus Pius and Marcus Aurelius, was a time of stabilization and peaceful transfer of power in the Roman Empire, through adoption and the choice of a sane successor. Hadrian, who took over power after the great Trajan, was not particularly favoured by him, and the adoption document could have been forged.
When in 86 CE, the father and mother of 10-year-old Hadrian died, later Emperor Trajan and Publius Acilius Attianus (later Praetorian prefect of Trajan) decided to take care of him. Young Hadrian was brought up like other Romans from the upper classes – carefully and comprehensively. The young man showed the greatest interest in Greek literature, hence his later nickname “Graeculus”.
In 100 CE Hadrian married Vibia Sabina (who was 12 years old at the time) – the granddaughter of the Emperor’s sister. It was a great honour for Hadrian; it is possible, however, that the consent to the relationship resulted from the persuasion of Plotina – Trajan’s wife. As it turned out, however, the relationship was not successful, which was partly due to Hadrian’s homosexual tendencies.
Trajan’s dislike of Hadrian grew gradually. It could have resulted from the defiant and disobedient youthful behaviour of Hadrian, which displeased Trajan, who was known for his modesty and moderation. Moreover, the information coming to his ears about the unsuccessful relationship between Sabina and Hadrian certainly limited Hadrian’s promotions.
Apart from agreeing to marry a member of his family, Trajan gave no clear signals to prove that Hadrian was in his opinion particularly favoured or planned as a successor. Hadrian, despite some military experience he had, did not receive any commanding powers in the initial phase of the war with the Parthians. Moreover, in the years 111-113 CE an adult Hadrian, instead of receiving important posts and public offices, with Trajan’s consent, stayed in Athens in order to further explore the Greek world. Trajan did not grant Hadrian the status of a patrician or the title of the first consul – as Cassius Dio says.
When in 117 CE seriously ill, Trajan decided to return to Rome, Hadrian remained in Syria as provincial governor. Trajan, who was dying on the west coast of Turkey, did not explicitly say who would be his successor. Cassius Dio explicitly claims that Hadrian did not receive any clear support from Trajan. Plotinus, strongly supporting Hadrian – with whom she could even have a love relationship – probably sought to recognize him as the heir and adopted son of the emperor. Attianus, who was on his hand to proclaim an allied and known to him man from childhood, could certainly have been involved in the conspiracy.
Cassius Dio’s father, Apronianus, who was the ruler of Cilicia, reported that Trajan’s death was kept secret for several days so that Hadrian’s adoption would be carried out smoothly and his right to the throne would be properly secured. This indicates that Plotinus and Attianus – the wife of the former emperor and the praetorian prefect respectively – supported Hadrian, which was to give him sufficient legitimacy. It is possible that Plotinus encouraged or forced Trajan to sign the adoption document, or that the document was simply forged.
With the support of Plotinus, Attianus and the Syrian legions, the only formal issue was to send a letter to the Senate asking for recognition of his authority.
After taking power, Hadrian only had to face Trajan’s staunch allies: Nigrinus, Quietus, Palma and Celsus, who probably might have known the truth about Hadrian’s illegal takeover of power. They were all accused of treason and murdered on Atttianus’ orders. We do not know if the senators actually planned a plot. What is certain, however, is that Hadrian broke a given word in a letter to the Senate, that during his reign no senator would lose his life on his order; the praetorian prefect acted on his orders.
Regardless, Hadrian stabilized on the throne of Rome, and as it turned out, his rule was to be successful.