How was this made?
Seals during this time were made from lead, gold, bronze, or silver. The specific design we see on each side of the seal would be cast on a pair of circular dies, metal devices used to strike a seal. Then a boulloterion, a type of iron plier, would hold the two dies together.
The boulloterion, with the two dies, would be pressed onto two blank lead circles. It would then impress the design onto the lead, like pressing a design into modern playdough. The images and inscriptions would now be on the lead circles. There would be an empty channel through the center of the two pieces of lead that would allow a string to be tied to a document, connecting the seal to the document.
The two dies bearing the seal design remained with the ruler at all times, to prevent documents from being sealed without the ruler's permission. However, once a seal was made, it traveled with the documents to which it was attached.