Born Servius Sulpicius Galba; Galba came from a noble and wealthy family; though he had no connection by birth and only a very remote connection by adoption to any of the Julio-Claudian dynasty. Refusing encouragement by friends to make a bid for the empire after Caligula's assassination; Galba loyally served Claudius; and lived for most of Nero's reign in retirement. However; in 68 CE; he was informed of Nero's intention to have him killed; and he defected from Nero to save himself. After Nero's suicide; Balba was named Caesar and killed many soldiers upon his approach to Rome for making demands of him.

Galba's reign lasted little more than seven months; his cruelty and sentencing of many to death without trial turning the people and especially the military and Praetorian guard against him. Many legions refused to swear loyalty and rebelled against Galba; and Galba was assassinated while riding out to confront them. His reign began what would be known as the tumultuous Year of the Four Emperors.