Roman Legions Used the Testudo Formation to Become Nearly Arrow-Proof One of the most famous Roman battlefield tactics was the testudo, or “tortoise” formation. It transformed a group of soldiers into a moving armored shell. In this formation, legionaries stood tightly together and raised their large rectangular shields (scutum) to cover every exposed angle. Soldiers in the front held shields forward, while those behind lifted theirs overhead. This created a continuous barrier of wood and iron o