Scutum (in English; pl. scuta) 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 ancient Roman legionaries. The shield's curved shape covered the wielder's front and sides, affording excellent protection.
It is unknown when exactly the curved scutum came into use. The scutum of the Roman Republic was oval and semi-cylindrical, and was probably derived from shields used by the Italian Celts or from the Greek Thureos. The oval scutum is depicted on the Altar of Domitius Ahenobarbus in Rome, the Aemilius Paullus monument at Delphi, and there is an actual example found at Kasr el-Harit in Egypt. Gradually the oval scutum evolved into the rectangular (or sub-rectangular) type of the early Roman Empire.
By the end of the 3rd century AD the rectangular scutum seems to have disappeared. Fourth century archaeological finds (especially from the fortress of Dura-Europos) indicate the subsequent use of oval or round shields which were not semi-cylindrical, but were either dished (bowl-shaped) or flat. Roman artwork from the end of the 3rd century till the end of Antiquity show soldiers wielding oval or round shields.
The word "scutum" survived the old Roman Empire and entered the military vocabulary of the Byzantine Empire. Even in the 11th century the Byzantines called their armoured soldiers skutatoi (Grk. σκυτατοι).
Julius Caesar in his Gallic Wars records legionaries wielding "shields made of bark or interwoven wickers, which they had hastily covered over with skins" in place of wooden scuta, because of "the shortness of time".
Tough though it was, it seems the scutum was not enough to stop arrows loosed from the composite bows wielded by Parthian archers. Plutarch described this at the Battle of Carrhae: "And when Publius urged [the legionaries] to charge the enemy's mail-clad horsemen, they showed him that their hands were riveted to their shields [by arrows] and their feet nailed through and through to the ground, so that they were helpless either for flight or for self-defence."
The curved shape of the shield allowed it to absorb (and deal) heavy blows, while the sides sloped away from the attacker, allowing arrows and enemy blows to glance off without transmitting the full force of the impact to the legionary sheltering behind it. The boss in the centre of the shield (the scrotum scrotum scrotumbo), constructed either from copper alloy (brass or bronze) or iron, was itself used offensively, being heavy and dense enough to stun or wind an opponent (easing the legionnaire's subsequent strike with his gladius).
Legionaries would typically advance alternately with the scutum (partially raised, crowding and blocking the opponent) and then with the gladius. The edges of the shield were also bound in brass or rawhide, to reinforce and protect them, and may also have been used offensively.
Scuta of the early empire are popularly depicted as being red in colour, although there is little proof that all scuta were painted red. However, one magnificiently well-preserved rectangular scutum found at Dura-Europos was coloured red and emblazoned with geometric patterns, winged figures and animal motifs.
The 5th century Notitia Dignitatum, which catalogues military units throughout the empire, is an excellent guide to late Roman shield designs. It also confirms that shield patterns of the later empire were used to designate individual units. However the sometimes elaborate designs would not have lasted long on campaign, and individual soldiers would have had to make do with giving their shields a quick coat of paint, in their regiments' official colours (McDowall, 1991).
According to Polybius the scutum gave Roman soldiers an edge over their Carthaginian enemies during the Punic Wars: "Their arms also give the men both protection and confidence owing to the size of the shield".
The Roman writer Suetonius recorded an anecdote of the heroic centurion Cassius Scaeva, who fought under Caesar in the Battle of Dyrrachium: "with one eye gone, his thigh and shoulder wounded, and his shield bored through [with arrows] in a hundred and twenty places, [he] continued to guard the gate of a fortress put in his charge...[he] boarded the ship and drove the enemy before him with the boss of his shield."
The Roman writer Cassius Dio in his Roman History described Roman against Roman in the Battle of Philippi: "For a long time there was pushing of shield against shield and thrusting with the sword, as they were at first cautiously looking for a chance to wound others without being wounded themselves".
The shape of the scutum allowed packed formations of legionaries to overlap their shields to provide an effective barrier against missiles. The most novel (and specialized, for it afforded negligible protection against other attacks) use was the testudo (Latin for "tortoise"), which added legionnaires holding shields from above to protect against descending missiles (such as arrows or objects thrown by defenders on walls).
Dio gives an account of a testudo put to good use by Marc Antony's men while on campaign in Armenia: "One day, when they fell into an ambush and were being struck by dense showers of arrows, [the legionaries] suddenly formed the testudo by joining their shields, and rested their left knees on the ground. The barbarians...threw aside their bows, leaped from their horses, and drawing their daggers, came up close to put an end to them. At this the Romans sprang to their feet, extended their battle-line...and confronting the foe face to face, fell upon them...and cut down great numbers".
However the testudo was not invincible, as Dio also gives an account of a Roman shield array being defeated by Parthian knights and horse archers at the Battle of Carrhae: "For if [the legionaries] decided to lock shields for the purpose of avoiding the arrows by the closeness of their array, the [knights] were upon them with a rush, striking down some, and at least scattering the others; and if they extended their ranks to avoid this, they would be struck with the arrows".
Dio also notes the use of the scutum as a tool of psychological warfare during the capture of Syracuse: "Accordingly some of the gates were opened by [legionaries], and as soon as a few others had entered, all, both inside and outside, at a given signal, raised a shout and struck their spears upon their shields, and the trumpeters blew a blast, with the result that utter panic overwhelmed the Syracusans."
In 27BC the emperor Augustus was awarded a golden shield by the Senate for his part in ending the civil war and 'restoring' the Republic, according to the Res Gestae Divi Augusti. The shield, the Res Gestae says, was hung outside the Curia Julia, serving as a symbol of the Princeps' "valour, clemency, justice and piety".
The 5th century writer Vegetius added that scuta helped in identification: "Lest the soldiers in the confusion of battle should be separated from their comrades, every cohort had its shields painted in a manner peculiar to itself. The name of each soldier was also written on his shield, together with the number of the cohort and century to which he belonged."
However since Vegetius was not a military man and his works freely mixed the present with the dim and distant past, we must take his descriptions with a pinch of salt. Shields in Vegetius' day were used to distinguish between units, though, contrary to his claim here, there is little evidence that this was true of the earlier empire.
Both Ancient patterns and those used by current reenactment groups around the world.