In 66 AD, a revolt was occurring in the Roman province of Judaea. Jews were rebelling and the governor of the province was killed in the fighting. Cestius Gallus, governor of Syria arrived in September with Legio XII Fulminata to restore order. He was able to take back parts of Judaea, but failed to take the Temple Mount after a nine-day siege and fell back to the coast. He was ambushed on the way, and of the 30,000 troops at his disposal when he arrived, escaped with heavy losses and died in Syria in 67, leaving Judaea lost as a Roman province. Nero replaced Gallus after his death with Gaius Licinius Mucianus as governor of Syria, and charged Titus Flavius Vespasianus, who was stationed in the area of Judaea with crushing the rebellion.
Vespasian arrived in 68 AD with two legions, eight squadrons of cavalry and ten auxiliary cohorts. His son, Titus, joined him from Alexandria with another legion. Instead of directly assaulting Jerusalem and the bulk of the rebel forces, Vespasian and Titus started chipping away at the strongholds of the outlying areas. After a 47-day siege, Galilee and Jodapatha were back under Roman control. Vespasian, with Legio X Fretensis, destroyed Jericho in June, 68. Losing ground, the rebels retreated to Jerusalem, throwing the city into chaos. The Zealot factions of the northern revolt were joined by the arriving Edomites, and they both began fighting the Sadducee Jerusalemites. The infighting lasted into 69 AD.
Meanwhile, civil war had erupted in the Roman Empire. Nero was killed in June of 68 and Galba declared himself emperor. Vespasian left the fighting in Judaea to Titus while he headed to Egypt to secure the vital grain supply for Rome. During his time in Egypt, Otho murdered Galba in January of 69 and took the throne. Otho only lasted three months before he committed suicide while Vitellius and his forces were advancing to take Rome. Otho’s loyalists, along with Mucianus in Syria and the troops in Egypt, convinced Vespasian to accept the title of emperor on July 1, 69 AD. Even with Vespasian being a seasoned and respected general, and having the support of Syria and Egypt, Vitellius still had the advantage – the empire’s best troops were stationed in Gaul and the Rhine.
Trouble started brewing for Vitellius quickly, however, as the armies in Moesia, Pannonia and Illyricum switched sides and declared for Vespasian. Marcus Antonius Primus led the troops into Italy from the northeast and defeated the Vitellian army waiting at Bedriacum. They continued on and sacked Cremora before marching on Rome. Vitellius made peace with Antonius, but the Praetorian Guard forced him to retain his seat, thus causing confusion and the army marched into the city. Vitellius was found hiding and dragged out, driven to the Gemonian Stairs and executed.
Vespasian, upon hearing the news of the death of Vitellius, forwarded the much-needed grain from Egypt and headed to the capital. He was declared emperor by the Senate in December of 69, while still in Egypt.