Origins and family life
He was born as Servius Sulpicius Galba near Terracina, "on the left as you go towards Fundi" in the words of Suetonius.
Through his paternal grandfather ("more eminent for his learning than for his rank — for he did not advance beyond the grade of praetor" and who "published a voluminous and painstaking history", and, according to Suetonius, predicted his rise to power), he was descended from Servius Sulpicius Galba. Galba's father attained the consulship, and although he was short, hunchbacked and only an indifferent speaker, was an industrious pleader at the bar.
His mother was Mummia Achaica, the granddaughter of Lutatius Catulus (cos. 78 BC) and great-granddaughter of Lucius Mummius Achaicus. They only had one other child, an elder son called
Gaius who left Rome after squandering the greater part of his estate, and committed suicide because Tiberius dishonored him by preventing him from taking part in the allotment of the provinces in his year. His father married a second wife, Livia Ocellina, a distant kinswoman of the empress Livia. She later adopted Galba, so he took her names, remaining Lucius Livius Ocella Sulpicius Galba until becoming emperor.
His was a noble family, and he was a man of great wealth, but was unconnected by birth and only very, very remotely by adoption with any of the first six Caesars. In his early years he was regarded as a youth of remarkable abilities, and it is said that both Augustus and Tiberius prophesied his future eminence (Tacitus, Suet. Galba 4; Dio 57.19.4).
His wife, Aemilia Lepida, however, was connected by the marriages of some of her relatives to some of the Julii-Claudii. They had two sons, probably Gaius and Servius (most likely Livius Ocella Galba), who died during their father's life. The elder son was born circa 25 AD. Hardly anything is known about his life as he died young. He was engaged to his step-sister Antonia Postuma, but they never wed, which leads modern historians to believe that he died during this time. Their engagement is dated to 48, and that is generally believed to be his time of death.
The date of birth of the younger son occurred later than 25 but before 30. This Galba outlived his older brother. He was a quaestor in 58, but he was never seen in politics after that. His time of death is generally believed to be around 60 AD. Galba Minor was never married and had no children.
Additionally, Suetonius's description of Galba was that "In sexual matters he was more inclined to males, and then none but the hard bodied and those past their prime". This seems to be the only case in Roman history where a named individual male is stated to prefer adult males.
He became Praetor in 20, and consul in 33; he earned a reputation in the provinces of Gaul, Germania, Africa and Hispania for his military capability, strictness and impartiality. On the death of Caligula, he refused the invitation of his friends to make a bid for the empire, and loyally served Claudius. For the first half of Nero's reign he lived in retirement, until 61, when the emperor bestowed on him the province of Hispania Tarraconensis.
In the spring of 68, Galba was informed of Nero's intention to put him to death, and of the insurrection of Julius Vindex in Gaul. He was at first inclined to follow the example of Vindex, but the defeat at Vesontio (Besançon) and suicide of the latter renewed Galba's hesitation. It was said that the courtier Calvia Crispinilla was behind his defection from Nero.
The news that Nymphidius Sabinus, the Praetorian Prefect, had given him his favour revived Galba's spirits. Until now, he had only dared to call himself the legate of the senate and Roman people; after Nero's suicide, he assumed the title of Caesar, and marched straight for Rome.
Following Nero's death, Nymphidius Sabinus sought to seize power prior to the arrival of Galba, but he could not win the loyalty of the Praetorian guard and was killed. Upon Galba's approach to the city in October, he was met by soldiers presenting demands; Galba replied by killing many of them.