In the context of English chivalry and feudalism, the caparison (or trapper) was an elaborate textile covering for a knight's destrier or charger. Beyond its decorative purpose, the caparison served a vital functional role in the late medieval period, protecting the horse's leather barding from the elements and dampening the impact of arrows. Its most critical heraldic function was the visual identification of the rider; in an era where the closed helm obscured the face, the repetition of the coat of arms on the horse’s flanks ensured the knight’s lineage and status were immediately recognizable across the field of battle or the tournament list.
Crafted from rich materials such as velvet, silk, or baudekin, these coverings were often sumptuously embroidered with gold thread and appliquéd with the wearer's charges. By the 14th century, the caparison had evolved from a simple surcoat for the horse into a formal statement of dynastic pride, used extensively in royal entries, state funerals, and the elaborate pageantry of the Garter ceremonies. As heavy cavalry transitioned into more mobile forms during the Renaissance, the functional armored caparison gave way to the purely ceremonial housings seen in the modern Royal Mews.