<P> By the end of the 3rd century 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 . </P> <P> The word "scutum" survived the Roman Empire and entered the military vocabulary of the Byzantine Empire . Even in the 11th century, the Byzantines called their armoured soldiers skutatoi (Grk . σκυτατοί). </P> <P> The scutum was a 10 - kilogram (22 lb) large rectangle curved shield made from three sheets of wood glued together and covered with canvas and leather, usually with a spindle shaped boss along the vertical length of the shield . The best surviving example, from Dura - Europos in Syria, was 105.5 centimetres (41.5 in) high, 41 centimetres (16 in) across, and 30 centimetres (12 in) deep (due to its semicylindrical nature), with a thickness of 5 - 6mm . It was likely well made and extremely sturdy . </P> <P> The scutum is light enough to be held in one hand and its large height and width covered the entire wielder, making him very unlikely to get hit by missile fire and in hand - to - hand combat . The metal boss, or umbo, in the centre of the scutum also made it an auxiliary punching weapon as well . Its composite construction meant that early versions of the scutum could fail from a heavy cutting or piercing blow which was experienced in the Roman Campaigns against Carthage and Dacia where the Falx and Falcata could easily penetrate and rip through the scutum . The effects of these weapons prompted design changes that made the scutum more resilient such as thicker planks and metal edges . </P>

What is the roman shield made out of