Although the shield of legionaries was essentially the large rectangular shield (shown in the lower left hand side of the picture to the right) other types of shield were also used, for example cavalry would use rounded shields.
The exact shape of the shield of standard legionaries varied through time but essentially retained its underlying shape, construction and function. It was large and curved so that the impact of incoming blows would be partially deflected and hence reduced. A metal semi-sphere in the centre of the shield allowed it to be used offensively in a similar manner to the crowd control techniques of modern police forces.
The shield is believed to have been constructed very much like modern plywood curved over steam. The cross-grain of successive sheets adds strength whilst keeping overall weight to a minimum. There are no existing examples to prove this though the shield of Dura Europos is a wonderful indication of what they were like: It is little more than a metre in height and 66cm across and about 0.5 cm in thickness. As well as being a wonderful example of shield it also happens to be one of the few extant examples of Roman art or Roman painting on a surface other than mortar.
Other types of shield were well known and popularly used as the armour of various types of gladiator
. The drawing of a highly decorated shield with a Medusa’s head and olive motives is shown left. The shield in question was found in Pompeii and would probably have been used for parading rather than actual fighting.
Last but not least we have some insights into some designs used on ancient Roman shields through one of the only surviving documents of late roman government. Though the “Codex Spirensis” has been lost some time in the 17th century copies of it have survived and pages within it give examples of the different shields for various military comands and regiments.