What is the name of the Roman military formation that allowed for greater mobility and flexibility in battle?

The Roman military formation known for its greater mobility and flexibility in battle is the Legion. Legions were comprised of heavily armed infantrymen called legionnaires and were organized into smaller units, allowing them to maneuver effectively on the battlefield. This structure was crucial for adapting to different combat situations, including open-field battles and urban warfare.

Unlike the phalanx, which was a tight formation popular in Greek warfare that emphasized massed ranks and heavy shields, the Legion's organization enabled Roman troops to spread out and engage the enemy more dynamically. The centuria refers to a subdivision of the legion, typically made up of about 80-100 men, but it doesn't represent a formation itself. The testudo, or tortoise formation, was a specific tactic within the legion, used primarily for protection during sieges, but it didn’t encompass the broader flexibility that the legion as a whole provided.

This adaptability was a key factor in the Roman military's effectiveness, allowing it to conquer territories across Europe, North Africa, and parts of the Middle East.