So far we have seen Augustus build a succession of heirs, only to be disappointed by repeated deaths.
His moves in the succession combine four principles, NO MORE WAR, GIRLS ARE MUMS, DADS ARE BEST, AUGUSTUS LOVES LIVIA.
Here is a summary of Augustus’ attempts to provide a succession of strong male heirs.
Augustus lacks a son. He decides his nephew Marcellus (son of his sister, grandson of his biological father, Gaius Octavius) will make a suitable father for the children of his daughter Julia 1. This simple plan fails due to Marcellus’ death.
Then accepts his unrelated stepson Tiberius, as a father of heirs. When Tiberius’ marriage to Julia fails, and it is clear that she will have no more sons (in fact she gets banished), Augustus is forced to consider Tiberius as an heir and adopts him. Augustus really wants a biological heir and so also adopts Julia’s third son by her previous husband, but later rejects him as unsuitable to be an heir. He has now run out of Julia’s sons, but there are still daughters.
Faced with the prospect of seeing his succession pass out of his biological line to Tiberius, Augustus brings in his great nephew, Tiberius’ nephew, Germanicus, who has descent from Augustus’ sister Octavia. Germanicus is to marry one of Julia’s daughters and keep the succession in Augustus’ biological family. Tiberius and his son lack biological relatedness to Augustus. Tiberius’ son is placed after Germanicus in the succession and given a suitable marriage which will produce children descended from Augustus’ father, but not Augustus himself.
The rest is just swapping off. Here are the Julio-Claudians who ruled.
In 14 AD Augustus died. Tiberius succeeded, as planned. During his reign he killed off several of Augustus’ descendants, including his own ex-wife, Julia 1, Agrippina, wife of Germanicus, and her two elder sons. Germanicus himself died of disease or poison in 19 BC. When Tiberius finally died in 37 AD, he had kept the peace for quarter of a century, although the imperial court had become a dangerous place. His son had predeceased him, possibly murdered by his wife, and Tiberius, now embittered and absorbed in his own world of vice and paranoia, allowed his line to die out.
Since Tiberius’ son was dead, a son of Germanicus followed him, as Augustus had intended. A survivor of the massacre of his family, the Emperor Gaius Julius Caesar, known as Caligula was reputedly mad. His bloody reign ended with his assassination in 41 AD. The line of Germanicus’ sons was exhausted, although daughters remained. Caligula left no heir.
The next Emperor was Claudius, brother of Germanicus, a descendant of Augustus’ father. He had never been intended as an heir – he was lame and Augustus viewed him as half-witted. Tiberius never saw him as a rival, and Caligula made him a figure of fun. Now, in the confusion of the assassination, he became Emperor. Claudius already had a son and a daughter. But in 49 AD Claudius married into Augustus’ bloodline, cementing his claims on the Augustan succession. This involved incest – he chose his niece, Caligula’s sister, Germanicus’ daughter, great granddaughter of Augustus himself, and, like Claudius, descended separately from Augustus’ sister . Names in the imperial household were departing from tradition and becoming very confusing. So we will call her Agrippina 2, to distinguish her from Agrippina 1, wife of Germanicus.
When the marriage took place, Agrippina 2 already had a son, Nero, by a previous marriage who had a double claim to Augustan descent, both from Augustus and from his sister. Claudius was only descended from Augustus’ sister. As a result of Augustus’ back-up heir plans, there were a number of people around with some sort of relatedness to him and his father.
Agrippina 2 was a dangerous bride. She had survived the killings of both parents and two brothers, and she had also steered her way through her brother Caligula’s murderous court. The story is that Claudius could not see through his young wife’s ambition for her own son. When Claudius’ son died young, it was said he had been poisoned by his stepmother. Left without an heir, Claudius adopted Agrippina’s son Nero and made him his heir. As you might expect by now, Nero also married Claudius’ daughter, his stepsister and first cousin once removed. Their son would be Claudius’ grandson (and his great nephew) and descended in multiple ways from Augustus and his sister. When Claudius died in 54 BC, allegedly poisoned by his wife, Nero became Emperor.
However, once he became Emperor, Nero’s concern for the Augustan succession was minimal. There was no grandson for Claudius. After Nero had established his rule, he murdered his mother and had his wife put to death. He made two other legal marriages as well as two irregular marriages, but had no children who survived infancy. In 68 AD his military commanders rebelled and he committed suicide. Civil War followed and the Augustan succession was over. Augustus had prevented Civil War for nearly 100 years. But his concerns for promoting his biological line in the succession had made the imperial family a brutal and murderous place. The traditional morality which Augustus promoted in his legislation was nowhere more flouted than in the distorted relationships, scandals and cruelties which typified his own family.