Final answer:
A Roman military legion typically consisted of approximately 5,400 infantry and specialists, alongside 120 cavalry, organized into cohorts and centuries, all led by centurions.
Step-by-step explanation:
A legion in the Roman military was a comprehensive unit that typically included around 5,400 infantry and specialists, along with an additional complement of 120 cavalry. In its classic structure, each legion was divided into 10 cohorts, each consisting of 480 men. Cohorts were further subdivided into six centuries of 80 men, which were each commanded by a centurion.
A century was then divided into 8 squads of 10 men, also known as 'tentmates', who shared their daily life and duties. Alongside these combat troops, the legion included a significant number of non-combatant specialists such as engineers, smiths, and cooks, making it a self-sufficient unit capable of extended operations in hostile territories.
The structure and organization of Roman legions allowed them to be a cornerstone of military might in Roman times, with their readiness and versatility playing a critical role in the expansion and defense of the Roman Empire.