When we think of an archive, we usually imagine mountains of paper, sheets grouped in a more or less orderly fashion that tell us stories of a distant past.
It is surprising, however, to discover how much more than "simple" written documents there is. An archive is a universe made up of small details, techniques and materials that were used across the yearsto validate the authenticity of deeds. Seals are certainly among the most fascinating of these tools.
The use of affixing a mark on objects to demonstrate ownership or guarantee that they were intact runs through human history and reaches a precise legal connotation in the Middle Ages becoming one of the fundamental tools for authenticating deeds.
The most widespread materials in the West were metal (in late Latin they were called bullae, hence the English term "bull" to mean "papal edict") and virgin wax.
In the first image we see a papal lead seal, among the many preserved in the Fabbrica del Duomo's Archive. It is a metal disc measuring 35 mm in diameter and 4 mm thick: it is attached to the parchment by a string running through two holes in the lower part of the document, specially folded to increase strength (in Latin: plica). In this case the cord is made up of yellow and red silk threads, to indicate that the deed was "de gratia". Otherwise, in the case of provisions “de iustitia” (legal orders, directives prescribing action) a hemp thread would have been used.
The seal has two faces. On the recto, according to an iconography that is repeated for all the pontiffs from Paschal II (1099-1118) to Pius II (1458-1464), we see the faces of the apostles Peter and Paul separated by a central cross and surmounted by their names abbreviated S (anctus) PA (ulus) - S (anctus) PE (trus). The entire seal and the two faces of the apostles are surrounded by a dotted border. The name of the pontiff changes on the verso depending on who was pope at the time.
The second image instead reproduces a "sub charta" seal, which was very widespread from the end of the 15th century. To make it, a small quantity of wax was poured on the lower part of the document on which a thin layer of paper was applied. By pressing the matrix, the upper sheet of paper was shaped on the underlying wax, revealing its design.
The use of seals as a means to authenticate documents dwindled from the 18th century onwards, as ink stamps became more common, but the memory of their century-long use has not been lost. It is well preserved in archives, the repositories of a history that is not only made up of great events and famous protagonists, but also and perhaps especially of small details.