Enarmes are the leather gripping straps attached to the back of shields throughout the Medieval period. Enarmes represented a significant advance in shield technology, as beforehand shields were held by a single bar that ran behind a boss. Enarmes were held in place by riveting through the leather and the facing of the shield, and reinforced with small, square-cut washers. Enarmes are visible on shields in the Bayeux Tapestry[citation needed].