scutum

The stereotypical shield of the ancient Roman legionary, tall and usually rectangular, with a distinctive outward vertical curvature. The scutum appeared among Romans in the fourth century BC, its precise origins unknown, and largely replaced the earlier clipeus, a circular shield adopted from the classical Greeks. Also often sported (in a wildly exaggerated form) by members of the Adeptus Astartes of Warhammer 40,000, as part of their general faux-Roman styling.