In Ancient Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 war

War

War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

fare, the testudo or tortoise formation was a formation used commonly by the Roman Legion

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

s during battles, particularly sieges. Testudo is the Latin word for "tortoise". The Greek term for this formation is "chelone" and during the Byzantine era, it seems to have evolved to what military manuals of the era call the "foulkon".

Description

In the testudo formation, the men would deploy very densely and position their shields

Scutum (shield)

Scutum is the Latin word for "shield", although it has in modern times come to be specifically associated with the rectangular, semi-cylindrical body shield carried by Roman legionaries.-History:...

 at the sides (rather than by the grip behind the umbo

Umbo

Umbo may refer to:*A shield boss* umbo , at the top of some mushrooms*The Umbo of tympanic membrane - a part of the human body*Umbo is the part of a Bivalve shell which was formed when the animal was a juvenile...

). The first row of men, possibly excluding the men on the flanks, would hold their shields from about the height of their shins to their eyes, so as to cover the formation's front. The shields would be held in such a way that they presented a shieldwall to all sides. The men in the back ranks would place their shields over their heads to protect the formation from above, balancing the shields on their helmets, overlapping them. If necessary, the legionaries on the sides and rear of the formation could stand sideways or backwards with shields held as the front rows, so as to protect the formation's sides and rear.

Plutarch

Plutarch

Plutarch then named, on his becoming a Roman citizen, Lucius Mestrius Plutarchus , c. 46 – 120 AD, was a Greek historian, biographer, essayist, and Middle Platonist known primarily for his Parallel Lives and Moralia...

 describes this formation as used by Mark Antony

Mark Antony

Marcus Antonius , known in English as Mark Antony, was a Roman politician and general. As a military commander and administrator, he was an important supporter and loyal friend of his mother's cousin Julius Caesar...

 during his invasion of Parthia

Parthia

Parthia is a region of north-eastern Iran, best known for having been the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire....

 in 36 BC:

"Then the shield-bearers wheeled round and enclosed the light-armed troops within their ranks, dropped down to one knee, and held their shields out as a defensive barrier. The men behind them held their shields over the heads of the first rank, while the third rank did the same for the second rank. The resulting shape, which is a remarkable sight, looks very like a roof, and is the surest protection against arrows, which just glance off it."

Cassius Dio writes about the testudo when describing the campaign of Mark Antony

Mark Antony

Marcus Antonius , known in English as Mark Antony, was a Roman politician and general. As a military commander and administrator, he was an important supporter and loyal friend of his mother's cousin Julius Caesar...

 in 36 BC: "this testudo and the way in which it is formed are as follows. The Baggage animals, the light-armed troops, and the cavalry are placed in the center of the army. the heavy-armed troops who use the oblong, curved and cylindrical shields are drawn up around the outside, making a rectangular figure, and, facing outward and holding their arms at the ready, they enclose the rest. the others who have flat shields, form a compact body in the center and raise their shields over the heads of all the others, so that nothing but shields can be seen in every part of the phalanx alike and all the men by the density of the formation are under shelter from missiles. Indeed, it is so marvelously strong that men can walk upon it and whenever they come to a narrow ravine, even horses and vehicles can be driven over it."

Tactical analysis

The testudo was used to protect soldiers from all types of missiles. It could be formed by immobile troops and troops on the march. The primary drawback to the formation was that, because of its density, the men found it more difficult to fight in hand-to-hand combat and because the men were required to move in unison, speed was sacrificed. As "foulkon," it played a great role in the tactics employed by the Byzantines against their eastern enemies.

The testudo was not invincible, as Cassius Dio also gives an account of a Roman shield array being defeated by Parthia

Parthia

Parthia is a region of north-eastern Iran, best known for having been the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire....

n cataphracts and horse archers at the Battle of Carrhae

Battle of Carrhae

The Battle of Carrhae, fought in 53 BC near the town of Carrhae, was a major battle between the Parthian Empire and the Roman Republic. The Parthian Spahbod Surena decisively defeated a Roman invasion force led by Marcus Licinius Crassus...

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