Augustus died peacefully on the 19th of August AD14 at Nola. Tiberius had been acting as co-regent and already had the key powers of tribunicia potestas and proconsular imperium which ensured that a smooth transition would take place.

The ancient historians mainly describe Tiberius's reign in terms of his adopted son Germanicus in his early reign and his praetorian prefect Sejanus in his later reign. Tiberius's retirement from Rome from AD26 to AD37 left the historians to speculate on his actions and report on the growing frustrations of a senate who were starting to realise the loss of their power that the principate represented. Due to these reasons it is very difficult to get an accurate picture of Tiberius and his reign.

Tiberius's reign started awkwardly and at the first meeting of the senate he showed reluctance to take over the role of princeps stating that was too big a burden to be met by one man. Tacitus sees this as Tiberius being hypocritical and it did cause confusion in the senate but Tiberius was probably either mirroring Augustus’s (pretended) reluctance to accept an expanded role in 27BC or attempting to get his power formally defined.

Not long after Tiberius became Emperor the legions in Pannonia (Hungary) and Germany (North Belgium / Lower Holland) mutinied. This time was chosen because the troops swore allegiance to a particular commander and with the death of Augustus they would be required to swear the oath to Tiberius. This gave the legions a rare opportunity to express their grievances from a position of strength and the protests were more about how they had been treated in the last few years of Augustus reign then about the accession of Tiberius. Tiberius acted quickly by sending Drusus and Germanicus to put down the rebellions

The Pannonian legions mutiny was based upon their long terms of service, low pay and conditions. Tacticus paints a picture of a few dissidents leading the troops, though it must be assumed that the grievances of the troops were genuine. Drusus quickly quelled this rebellion although Tacticus claims this was more through luck (the moon was seen to dim which was taken as a bad portent to the revolting troops) then any particular skill. The Germany legion revolt was based on similar reasons, although there are indications that manpower was much more stretched, for instance slaves had been drafted, which was a highly unusual measure, this would have been partially due to the lost legion of Varus in AD9 not being replaced. Tacitus also hints that they also wanted to make Germanicus the Emperor but this is probably not true and is related to the Rhine legions forcing Nerva to adopt Trajan at the time Tacitus was writing his history.

Germanicus did not cover himself with glory in stopping this rebellion and a number of his actions would have caused Tiberius great concern

Germanicus

Germanicus

Germanicus was the son of Tiberius's brother Drusus. He inherited the popular support of the people from his father (Drusus is often portrayed as Augustus's favourite and he was a favorite of the people for his conquests in Germany) and Tiberius is portrayed as being jealous and scared of him by the historians. Tiberius however treated both Germanicus and his own Drusus as equals and they were advanced in line with the three year age difference between them. They held consulships in 12 and 15 and were granted proconsular imperium in 14 and 17 respectively. In fact asking the senate to grant Germanicus imperium was one of the first act’s of Tiberius’s reign. Germanicus’s actions during the reign of Tiberius suggest he was a little impetuous and unthinking and there is a hint that Tiberius may have felt a little contemptuous towards him.

After Germanicus managed to quell the rebellion on the Rhine he led the troops over the Rhine to get them back into shape. Tiberius was probably not very enthused by this as his frontier policy was to keep the empire at the bounds set by Augustus. Tiberius would have accepted this as a way to destabilise and keep the Germanic tribes under control while building Germanicus's prestige. He allowed Germanicus to campaign over the Rhine from AD14-16 where he did win some good victories but these campaigns were costly in terms of expense and men and Germanicus almost suffered a similar massacre to that of Varus in AD9. After two years of campaigning Tiberius recalled Germanicus to Rome to celebrate a triumph, Germanicus initially wished to stay to defeat the Germans but Tiberius then also offered him the consulship and asked him to leave some glory for Drusus which was sufficient to convince Germanicus to return.

Germanicus celebrated a triumph in AD17, confirming him as successor and further adding to his prestige. He was then sent to the East to negotiate with a new king of Armenia with Parthia, a similar posting to the one Tiberius had under Augustus. Germanicus was successful and in AD18 he defeated the kingdoms of Cappadocia and Commagena and annexed them as provinces.

Tiberius had sent Calpurnicus Piso to be the governor of Syria and keep an eye on Germanicus. Unfortunately even though they had a formal friendship Piso hated Germanicus and refused to obey his orders. This came to a head when Germanicus appears to have gone to Egypt as a sightseer without Tiberius allowance (senators must get the princeps permission to visit Egypt) and while he was there he opened up the granary to the starving Alexandrians, both actions reflecting Germanicus's impetuousness and that he was not obeying Tiberius.

When Germanicus returned to Syria he found Piso had disobeyed all the orders he had left and so Germanicus renounced their friendship and Piso felt compelled to abandon his post. Before Piso left Germanicus fell ill and on his sickbed he accused Piso of poisoning him, called on his wife to avenge him and promptly died. When Piso left Syria Tiberius and the senate had sent a replacement governor, Piso upon hearing of Germanicus’s death returned to Syria and tried to seize power. This failed and he was sent back to Rome, charged with civil war offences and poisoning Germanicus.

The Funeral Procession of Germanicus

While this was happening Agrippina set out for Rome with his ashes in what was to become a huge public procession. Agrippina suspected Tiberius’s involvement in her husband’s death as she thought he was jealous of Germanicus. Tacitus claims that Tiberius did not participate in the mourning for Germanicus but this appears to be false from inscriptional evidence, it is likely that Tiberius took a step back so not to compete with Agrippina. This theory that Tiberius was involved wasn’t helped when Piso committed suicide during the trial. Tiberius ordered the trial to be completed anyway and Piso was found guilty and suffered official condemnation (damnation memoriae), this however did not clear Tiberius’s name. Agrippina remained convinced of Tiberius’s guilt and she became a rallying point for those who disliked Tiberius.

Sejanus
Sejanus came from a prestigious family with consular connections he was joint praetorian prefect with his father Strabo, but when Strabo was posted to be Prefect of Egypt in AD15 Sejanus was left as the sole praetorian prefect. He soon became one of Tiberius’s key advisors and increased his power through actions like moving all the Praetorian Guard into Rome. By AD20 he had a link to the imperial family when his daughter was promised to marry Claudius’s son (though the boy soon died).

Sejanus apparently seduced Drusus’s wife Lavilla and together they supposedly plotted to poison Drusus who died suddenly in AD23, it is uncertain if the poisoning rumours were true but Sejanus had the most to gain from this death. Drusus was known to dislike him and if he was having an affair with Drusus’s wife he may have decided to silence up before he upset Tiberius. After Drusus’s death Tiberius leaned more heavily on Sejanus and openly called him his partner. He was not however marked as successor as demonstrated when Sejanus asked Tiberius for permission to marry Lavilla (which would give him a claim to the thtrone) but Tiberius refused the request.

On Drusus’s death Tiberius did not have a successor of an appropriate age his options were
• His grandson Tiberius Gemellus who was very young.
• His uncle Claudius - Tiberius had earlier denied Cluadius a political career when Claudius had requested one.
• One of Agrippina and Germanicus’s three sons.

Agrippina the Elder

Agrippina had been vigorously promoting her sons but the fallout over the death of Germanicus had caused Tiberius to not like her very much and it was not hard for Sejanus to talk him into believing a conspiracy. In AD26 Tiberius left Rome for retirement in Capri and Sejanus started attacking Agrippina by charging her supporters with treason and they were either exiled or killed. When Tiberiius's mother Livia died in AD29 Sejanus became bolder and Agrippina and her son Nero were exiled while another of her sons Drusus was cast into prison. This left only Gaius (Caligula), who Tiberius had named his successor in the senate, to deal with.

At this stage Antonia (a very prominent lady of Rome she was Tiberius's sister-in-law and Germanicus's mother) sent a letter to Tiberius to warn him of Sejanus and Tiberius appears to have set a trap. In August AD30 Gaius was called to the safety of Capri. Tiberius then made Sejanus co-consul with himself for AD31 as well as a grant of proconsular imperium. This manoeuvre would have made Sejanus feel secure while allowing Tiberius to appoint a new praetorian prefect who he trusted in Sutorius Macro. In October of AD31 Tiberius sprung his trap and had Macro read a letter to the senate condemning Sejanus and calling for his arrest. To the joy of the people he was soon executed. It is possible that Tiberius had decided to use Sejanus as a caretaker until Gaius and Tiberius Gemellus came of age but Antonia’s letter made him realise how much Sejanus's derised power and that he would not be an ideal caretaker.

Sejanus’s death did not change Tiberius's attitude to Aggripina and he did nothing to help Agrippina and her other children and they soon died. What effect this had on Gaius is unknown but presumably it was not good.