Greave

A greave (from the Old French greve "shin, shin armour" from the Arabic jaurab, meaning ) is a piece of armour that protects the leg.

The primary purpose of greaves is to protect the tibia from attack. The tibia is a bone very close to the skin, and is therefore extremely vulnerable to just about any kind of attack. Furthermore, a successful attack on the shin results in that leg being rendered useless, greatly hampering one's ability to maneuver in any way. Greaves were used to counteract this. Greaves usually consisted of a metal exterior with an inner padding of felt. The felt padding was particularly important because, without it, any blow would transfer directly from the metal plating to the shin, rendering the piece of armour almost useless.

During Greek antiquity, greaves were mentioned in many texts, including Hesiod’s Shield of Heracles, Homer’s Iliad and Virgil’s Aeneid. In the Illiad, the Greek forces are commonly referred to as "well-greaved Acheans" (euknēmidas Achaious). While these are primarily mythological texts, they still dealt with warfare and the fact that greaves were mentioned is evidence that they were indeed in use. There are also non-fictional testimonies of their use among Roman light infantry (or hastati) from Polybius up to Vegetius. These greaves are thought to have been mass-produced by the Romans using presses on sheets of metal and then attaching lining, usually leather or cloth. While it is generally assumed that greaves were always worn in pairs, there is evidence that many wore just a single greave on the left or right leg. Many skeletons have been found buried with only a single greave, including gladiators and soldiers. People may have worn a single greave as a sign of status, as opposed to any practical use.

Greaves were common until around the ninth century, when they largely disappeared. There is not much evidence of their use until the second quarter of the thirteenth century. There were a few references to the use of greaves before then, most notably the Bible’s Goliath and the Trinity College Apocalypse, but the lack of other evidence suggests that they were uncommon at the time. Almost all greaves used at this time are known as “Demi-greaves”, or greaves that only protected the shin. Early in the fourteenth century, many illustrations were found showing “closed greaves”, or greaves that protected the entire leg. Closed greaves are made of two plates joined on the outside by hinges and fastening with buckles and straps on the inside.

...
Wikipedia