In 66 CE, long-standing Greek and Jewish religious tensions worsened after Jewish worshippers witnessed Greek civilians sacrificing birds in front of a local synagogue in Caesarea and complained to the authorities. The Roman garrison did not intervene, leading to the triggering of popular protests against Roman taxation. The protests were ignored by the governor until public attacks in Jerusalem on Roman citizens and others accused of having Roman sympathies, led the army garrison to intervene. The soldiers were attacked as they moved through the city by an increasing proportion of the Jewish residents; many troops were killed and the rest evacuated Jerusalem. As news of this action spread, many other towns and Jews joined the rebellion. Fearing the worst, the pro-Roman king Agrippa II and his sister Berenice fled Jerusalem to the Galilee.
Intervention of the Syrian Legion
, the legate of Syria, marched on Jerusalem with Legio XII Fulminata and auxiliary troops, with an aim of crushing the rebels and restoring order. Such had been the standard Roman reaction to uprisings at the time. All available troops were mustered, formed into a column and sent to confront its perceived centre. Ideally, such a show of force would have allowed the Romans to regain the initiative and prevent the rebellion from developing and growing stronger. Gallus conquered Bezetha, in the Jezreel Valley, soon to be the seat of the Great Sanhedrin, but was unable to take the Temple Mount; he now decided to withdraw and wait for reinforcements.
The battle
Withdrawing towards the coast from Jerusalem, the Romans were closely pursued by rebel scouts. As they neared the pass of Beth Horon, they were ambushed and came under attack from massed missile fire and arrows. They were then suddenly rushed by a large force of rebel Judean infantry. The Romans could not get into formation within the narrow confines of the pass and lost cohesion under the fierce assault. The equivalent of an entire legion was destroyed, with 6,000 troops killed, many wounded, and the rest fleeing in disarray. Gallus succeeded in escaping with a fraction of his troops to Antioch by sacrificing the greater part of his army and a large amount of materiel.
Aftermath
After the battle, the Jewish rebels went through the Roman dead stripping them of their armor, helmets, equipment, and weapons. Soon after his return, Gallus died, and was succeeded in the governorship by Mucianus. This major Roman defeat encouraged many more volunteers and towns in Judea to throw their lot in with the rebels. A full-scale war was then inevitable. The shock of the defeat convinced the Romans of the need to fully commit to crushing the rebellion regardless of the effort it would require. Emperor Nero and the senate then appointed Vespasian, the future Emperor, to bring the Roman army to Judea and crush the rebellion with a force of four Legions.
Literature
In M.C.Scott's historical novel, Rome: The Eagle of the Twelfth, the author describes the Battle of Beth Horon and the destruction of the XII legion.