Wax and clay seals have always struck me as a rather imperfect security mechanism. Better than nothing, of course, but imperfect. So I was interested to learn that Los Alamos National Laboratory's Vulnerability Assessment Team had conducted a study, "Were ancient seals secure?"

Abstract: Forgeries of ancient seals have been found in modern times, but there has been little previous analysis of how much security ancient seals might have offered. In this paper, we demonstrate four different vulnerabilities of clay seal impressions using attack methods and materials that were available thousands of years ago. The success of these attacks suggests that ancient stamp and cylinder seals may have been highly vulnerable to spoofing.

However, the authors don't mention any known instances of ancient seal-spoofing, let alone any consequential instances of spoofing. But the authors are not historians, so I don't take this as indication that it never happened.

So, did a forged seal ever seriously compromise a political or military operation?

A forged seal could be effective in at least two ways. First, you could send out counterfeit orders, telling a vassal to march west when the king or whoever really wants the vassal to march east. Second, you could conceal an act of espionage by resealing an order: the vassal receives the order to march east, and because the seal is intact the vassal does not take extra precautions, only to be ambushed along his route. You can imagine plenty of other scenarios.

Given the several thousand years of history when seals were an important security mechanism, I imagine that a forged seal was pivotal at one point--but I haven't found any examples yet.

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    Yes, there was a guy named Hamlet who was a prince of Denmark and his stepfather/uncle tried to have him murdered, but Hamlet found out and forged a new order with a new seal that executed his guardians instead of him, thereby changing the whole history of Denmark. Commented Jan 13, 2015 at 15:56
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    @TylerDurden: That's pretty funny. But it's exactly things like that I've wondered about. If someone got an odd or unexpected order that had an official seal on it, would they carry it out unquestioningly? Or would they say, "Seals are imperfect, I'll wait for further confirmation." Also, that's a good example of why seals might not be that effective in civil wars or dynastic struggles.
    – two sheds
    Commented Jan 13, 2015 at 16:02
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    I agree that the first thing to confirm is the proposition that official seals were trusted (by themselves) as being secure. In order for that to be true, any and all of the potential recipients of sealed orders would need to be able to authenticate (with a certain degree of precision) the official seals of anyone who was likely to send them a sealed order. Are there any records of authentication processes or procedures for sealed documents?
    – Steve Bird
    Commented Jan 13, 2015 at 21:45
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    There are a lot of references to forged orders and edicts in Chinese history - though they usually used ink seals. eg: en.wikipedia.org/wiki/Zhu_Ci There were also a lot of forged Papal edicts used to justify claims over territory etc. eg: en.wikipedia.org/wiki/Donation_of_Constantine Were these specific failures of a seal? Probably not. I'm guessing it was only one of many layers of authenticity. Having a sealed message embossed with gold delivered by trusted Prince so-and-so accompanied by lavish gifts is probably the ultimate in period authentication techniques.
    – Jasta
    Commented Jan 14, 2015 at 0:42
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    @Jasta: Thanks, the Zhu Ci reference is interesting. The Donation of Constantine is a very different kind of forgery from what I'm asking about in a number of ways though. As for layers of authenticity, you're right that there would be many degrees possible. But if you think about the number of sealed messages that might be going back and forth in the administration of an empire to out-of-the-way garrisons or units in the field, not every message will be gold embossed or delivered by a trusted Prince. That's when the question, "Trust the seal or not?" is the most immediate and consequential
    – two sheds
    Commented Jan 14, 2015 at 1:02

2 Answers 2


Seals were less about verification of identity, and more about verification of non-tampering. As with all significant documents today, the presence (and seals or signatures) of witnesses was the most important aspect of identity- and authentication-verification. Placing the author's/authorizer's seal at the bottom of the written text was more about preventing after-the-fact tampering, and in-transit reading.

As an example: When on June 15, 1815, Ney and his one-horse cart caught up to the Grande Armee in Charleroi, Napoleon had to signal to Generals Reille and D'Erlon that Ney had Imperial authority as the Left Wing commander. He solved this dilemma neatly by giving Ney command of the Imperial Guard Red Lancers (with the direction to "use them gently"). There could be no doubt about Ney's authority while he was escorted by such an esteemed regiment.

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    Thanks, it's an interesting example and is informative about 19th century administrative practices. I'm going to leave the question open though. According to your first paragraph, a spoofed seal would allow for significant espionage opportunities. Also, the 19th century French military is a sophisticated administrative regime. Seals still might have been used to verify identity in ancient Sumer, feudal Europe, etc. So I'm still hopeful that I might get an example of a successful act of seal forgery.
    – two sheds
    Commented Jan 15, 2015 at 13:35

I was just reading The Tartar Khan's Englishman by Gabriel Ronay and in it he states how King Bela had lost his seal in the fleeing of a battle and this seal was used by the Mongols (through the Englishman who spoke Hungarian) to issue edicts ordering the militia not to muster and for peasants to return from hiding to the fields (where they could later be easier found and killed)

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