Final answer:
The military forces of Rome were called legions, which were professionalized units consisting of about five thousand soldiers. Legions played a crucial role in Rome's military conquests throughout the provinces of the Roman Empire.
Step-by-step explanation:
The military forces of Rome were called legions. A legion was a professionalized force that consisted of about five thousand soldiers and was commanded by a legate. These legions were stationed throughout the provinces of the Roman Empire and played a central role in Rome's military conquests. Soldiers served a sixteen to twenty-year term and were paid at the end of their service.