Diplomatics (Gr. , a doubling; hence anything folded double, as a written document), the science of the knowledge of ancient documents, and especially of their age and authenticity. The charters of grants from sovereigns to individuals and corporations were formerly called diplomas, and the word is applied to all letters, documents, and pieces of writing of a public nature that have come down to us from the middle ages and the subsequent centuries. The ancient public documents of the Greeks and Romans have perished, except such as were inscribed on stone or metal. But a vast mass of manuscripts of the middle ages exists in Europe, whose dates and authenticity can only be settled by careful and skilful investigation. The quality of the parchment or paper and of the ink, and the style of the handwriting, are the means chiefly relied upon to determine the age of the document. Formerly ink was made of soot, and red ink made of vermilion was sometimes used. Those who apply themselves to the study of diplomatics can easily distinguish the ink and the parchment and paper of one epoch from those of another.
The variations in handwriting are also so great that by the character alone it is possible to pronounce within 40 or 50 years when any diploma was written. In Europe the study of diplomatics has been much cultivated. The standard book of reference on the subject is the Nouveau traite de diplomatique, pur deux Benedictins (6 vols. 4to, Paris, 1750).