Sigillography

Sigillography is the study of the seals used on documents. It is one of the auxiliary sciences of history. It has links to diplomatics, heraldry, social history, and the history of art.
This field of study was started in the 15th century by students of old artifacts. Then it became more well known in the 16th and 17th centuries. At first this field of study was thought of as part of diplomatics. But over time it became known as its own field of study.