Sigillography, also known by its Greek-derived name, sphragistics, is the scholarly discipline that studies the wax, lead, clay, and other seals used to authenticate archival documents. It investigates not only aspects of the artistic design and production of seals (both matrices and impressions), but also considers the legal, administrative and social contexts in which they were used. It has links to diplomatics, heraldry, social history, and the history of art, and is regarded as one of the auxiliary sciences of history. A student of seals is known as a sigillographer. Source: Wikipedia (en)