A signaculum is a general Latin term for a seal or sign produced by a stamp or signet ring,[1] used in modern scholarship in particular reference to Roman lead pipe inscriptions, brick stamps, bread stamps,[2] and the lead "dog tag" of Roman soldiers.
The signaculum of the Roman soldier was carried in a leather pouch suspended around the neck. The tag is thought to have had personal information for the purpose identifying the dead, in the same way a modern dog tag does, with a seal or stamp to authenticate it.
Although the origins of exactly when or why the Roman army decided to use the signaculum for their soldiers are not clear, there are, regardless, references to its use in some historical documents, which indicate its composition (lead), as well as the fact that it is given after it is determined a man is fit to serve the legion.In a document from 295, Maximilian of Tebessa, an early Christian martyr, is being recruited as an officer in the Roman army against his wishes:
There is some evidence that by the time of the late Roman army, it became common practice to instead give soldiers who were found fit for service in the legion an indelible Soldier's Mark, possibly to discourage desertion by making any former or deserting soldiers clearly discernible.
In De Re Militari (AD 390), one of the Roman military writer Vegetius Renatus states that after the initial selection process, a recruit is then placed through a four-month testing period to ensure his physical capability.
A neck ring with a tag served a similar purpose in identifying a fugitive slave. The ring was riveted so that it couldn't readily be removed. The tag contained information such as the owner's name, status, and occupation, and the "address" to which the slave should be returned.[3]
See also: Roman lead pipe inscription. Items made from terra cotta, lead, and other impressionable materials were often stamped with a maker's mark during manufacture.
It is possible that signacula that were carried by domestic workers were used as stamps to record usage of tools, and debts from one to another.[4]