In the Middle Ages, the use of unique seals to authenticate and enclose documents began with royalty, and over the centuries the practice widened to include religious institutions, knights, and free citizens. arises from a major project investigating seals and their use in medieval Wales, the Welsh Marches, and neighbouring counties in England. P.R. Schofield, E. A. New, and S. M. Johns provide important new insights into the history of medieval Wales and the English border counties. A ground-breaking treatment of seals as historical documents, it offers a new perspective on the history of medieval Wales and its periphery by addressing a variety of themes in terms of the insight that seals can offer the historian.