Final answer:
Vitellius was the third emperor during the Year of the Four Emperors, supported by Germania's legions but not by the eastern legions, leading to his defeat and execution.
Step-by-step explanation:
The main answer to the student's question about the third emperor during the Year of the Four Emperors who was supported by the legions in Germania but not by the eastern legions is Vitellius. Not explicitly mentioned in the provided information, Vitellius is known to have been the third emperor in this period, having taken power after Galba and Otho. However, he quickly faced opposition from Vespasian's forces, which were supported by the eastern legions. After a short reign, Vitellius was overthrown by Vespasian and executed in Rome in 69 CE. The Year of the Four Emperors was a turbulent period in Roman history characterized by rapid changes of power, ultimately leading to the establishment of the Flavian dynasty with Vespasian as the emperor.In conclusion, the Year of the Four Emperors reflects the volatility and political strife within the Roman Empire that occurred after the death of Nero. This period highlights the challenges of imperial succession and the significant role of military support in securing the throne.