What were the Roman legions mainly composed of?

The Roman legions were primarily composed of heavy infantry known as legionnaires, organized into smaller units called cohorts. Each legion typically consisted of around 4,800 to 5,200 soldiers, with the bulk being infantry who were heavily armed and trained for battle. Cohorts were the main tactical units within a legion, allowing for flexibility in maneuvering and combat. The structure of the legion was designed to create a highly effective fighting force, focusing on disciplined infantry formations and strategies, which were critical to the success of Roman military campaigns. While other components like cavalry, auxiliaries, and different types of troops were important in the Roman military, the core strength of a legion remained its infantry units, thus making this answer accurate.