Legio I Adiutrix

On Seprember 22, 66, Emperor Nero created the Legion I Italica who were mostly sailors. By becoming legionaires, they were entitled to Roman citizenship, so there were many volunteers. the new emperor dismissed them as riff-raff. An excerpt from the article:

"As his enemies closed in on him during his final days on the throne, Emperor Nero was desperate. Although Rome already had two legions in the city — Legio XI Claudia and Legio XV Apollinaris — he decided to form a third legion from the sailors of the Roman navy stationed at Misenum. The sailors were anxious for the opportunity because, like any other Roman legionary, they could now gain Roman citizenship. The would-be legion waited impatiently to be presented with their eagle and standards when Nero’s death in 68 CE brought a new emperor to the Roman Empire, the governor of Nearer Spain (Hispania Citerior), Servius Galba (r. 68-69 CE). The 5,000 sailors took their cause to him, but he was not as receptive as they had hoped.

The sailors desperately tried to present their case to Galba. However, he ignored them, refusing to listen, promising to hear their request later.
With his newly formed Spanish legion, Legio VII Gemina, accompanying him, Galba left Spain and in October arrived at Rome. Unfortunately for the new emperor, his long-awaited entry into the city soon turned into turmoil. Three miles outside Rome, Galba and his army were greeted by thousands of Roman citizens, welcoming him to their city. Among the throng of Romans were the sailors who desperately tried to present their case to him. However, he ignored them, refusing to listen, promising to hear their request later. Of course, this was not what the sailors wanted to hear. Preventing others from seeing or hearing the emperor speak, they continued to follow him, shouting their demands. At the Milvian Bridge that crossed the Tiber, the procession stopped. Upon seeing a handful of drawn swords, Galba ordered his cavalry to attack the mostly unarmed men. The result was bloodshed, and his violent arrival would bring him into direct conflict with the Misenum sailors, the Praetorian Guard, and the people of Rome. Roman historian Tacitus (l. c. 56 - c. 118 CE) in his History wrote of Galba’s entry into Rome and the effects it would have afterwards:

His entry into the capital, made after the slaughter of thousands of unarmed soldiers, was most ill-omened, and was terrible even to the executioners. As he brought into the city his Spanish legion, while that which Nero had levied from the fleet still remained. (History I. 6.)."