I've read many articles about them using clay tokens to ensure some authenticity of transactions, called Bulla, but I can't find any information about how they actually work.

Can anyone clarify?

It seems to suggest that if Steve buys 5 chickens from Bob, then he can write "Steve Owes Me 5 Chickens" on a piece of stone, and then bake it into a clay ball. Then this can be traded. But who keeps the clay ball? If you have an obligation, you can just throw it away and pretend it never happened. If it's Bob that keeps the token to prove Steve owes him, how does the ball itself prove anything? He could just lie and make his own clay ball with fake instructions inside.

There must be something I am not understanding about the security feature. Some articles suggest that tokens are inside the ball, rather than a contract, which is even more puzzling.

Edit: Also found this http://viking.som.yale.edu/will/finciv/chapter1.htm

Denise Schmandt-Besserat may have discovered the origins of writing on the surfaces of the clay bullae, but the mystery remains -- why did the ancient accountants of Uruk use a cumbersome bullae system for their records? Indeed bullae remained in use even after the full development of written script. The answer lies in the fact that they were more than accounting tools -- they were actual contracts.

Everything we think of as a financial instrument today is, in fact, a contract. A government bond, for instance, is a contract between the government and the bond-holder to guarantee a series of payments in the future. A share of stock is a contract between the shareholder and the corporation that guarantees participation in the profits of the firm, and a right to vote on management. Although contracts existed before the invention of writing, and even before the invention of bullae, the hollow clay balls and their tokens appear to be the earliest archaeological evidence of contracts. Each bulla found in the Inanna temple complex meant that someone -- and we don't know who, made a promise to give some commodities: jars of honey, sheep, cattle -- perhaps even days of work, to the temple. The writing on the outside of the bulla allowed the contracting parties to refer to the amount owed over the term of the contract, but the tokens inside, kept by the lender as evidence of the agreement, tangibly symbolized the obligation. This interpretation may explain other curious features of the bullae as well. Some of the envelopes are covered entirely in the impressions of cylinder seals -- the Mesopotamian equivalents of signatures. These undoubtedly represent a personal mark indicating the promise of the owing party. Bullae that are entirely covered in seal impressions seem to suggest that the owing party was concerned that the bulla holder might break open a small part of the bulla and insert some additional tokens.

We cannot really call the bullae the first financial instruments, because we do not know who the contracting parties were. We do not know whether the obligation is a return of a loan, or simply a tax or tribute to the temple. The bullae do not specify time (or at least Denise Schmandt-Besserat has not decoded the symbols for time) and they do not specify interest rates. All we know for sure is that they formalized commitments of future payments. The bullae were contracts that bridged a period of time -- from the moment when one party entered into an obligation, to the moment when the obligation was discharged.

But it's still unclear to me exactly what the tokens are for inside the bulla, if the bulla represents some kind of contract.

  • There is an old book (1992), I cannot really remember how the system works. But here's the book: Before Writing, Vol. I: From Counting to Cuneiform by Denise Schmandt-Besserat at Univ of Texas Press.
    – J Asia
    Sep 23, 2019 at 22:54

3 Answers 3


From Wikipedia:

In their oldest attested form, as used in the ancient Near and Middle East of the 8th century BCE onwards, bullae were hollow ball-like clay envelopes that contained other smaller tokens that identified the quantity and types of goods being recorded. In this form, bullae represent one of the earliest forms of specialization in the ancient world, and likely required skill to create.

Based on this alone, it seems to me that the makers of bullae served a function basically comparable to that of a notary public today. They were a third party attesting to the validity of the token inside. If I don't know you but I do recognize the bulla you have as one made by an authority I trust, and if I can also see that the bulla is unbroken (so that the token inside has not been replaced or tampered with) this greatly increases my trust in the validity of the token inside.

Just as with a notary seal and signature today, forgery would have been a possibility. I'm not sure how common this was historically, but if the system was widely used, it must have had at least some reliability. If the bullae were too easily faked or tampered with, you are right to think they would not be very useful. Or if the makers of the bullae were corrupt and willing to verify false tokens, this would also have been just as problematic and potentially discovered in time.

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    May also be worth adding a reference to any known laws regarding fraud from the time period if someone knows of a good reference. Also, forgery and con artist scams probably seem a lot less profitable in an era where catching a bad case of being dead was relatively easy and common... Sep 23, 2019 at 19:53
  • Ah, so they're just saying the tokens themselves aren't counterfeit? Because presumably you could just stamp the tokens rather than the envelope. I guess perhaps the tokens are easy to forge whereas the bulla is not. Although it seems cumbersome to have to create a bulla for transactions, especially as the quote says it requires skill to create one. @TheLuckless I read in some articles that forgery was rife back then, particularly shavings of silver/gold/other metals being mixed up. They used grains for currency to avoid this because you needed loads of them so it was hard to shortchange.
    – NibblyPig
    Sep 23, 2019 at 21:54
  • I've also updated my question cos I found another article that suggests they're more to do with contracts but I still don't get the point of the tokens if it's true, why not just write IOU 5 sheep and both stamp the piece of clay?
    – NibblyPig
    Sep 23, 2019 at 22:01
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    @TheLuckless Hossein Badamchi (2016) Fraud and Forgery in Old Babylonian Law may be relevant (but is unfortunately behind a paywall).
    – 0range
    Sep 23, 2019 at 23:11
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    @NibblyPig To put it simple, these clay bullae predate writing. After writing was invented, contents were also written on the outside of the bulla. But the writing is easier to fake, like adding another scratch and changing a number to a larger one. So is there was a dispute, the bulla could be broken to check tokens inside.
    – user28850
    Sep 24, 2019 at 16:07

It is important to realise that bullae pre-date any sort of writing. Originally, they could not contain enough information to form a full contract.

The tokens inside represented quantities of goods, such as sheep or jars of oil. They were used by Mesopotamian accountants, and one use might well have been just to keep track of temple property. Tokens were probably just held in leather bags originally. The bullae were a later development, with the advantage that to see the number of tokens inside, the bulla had to be broken open, and this would have been obvious. One possible use would have been as a bill of lading. The delivery man would be given a bulla at the start of the journey, and a priest could check that the number of jars of oil arriving at the temple was the same as had been sent. A broken bulla would imply the bill of lading had been tampered with on the journey. A seal would prevent a new bulla being created with different tokens inside and passed off as the original – the new bulla would lack the correct seal. A well-made seal would have carvings that would be too difficult to reproduce.

It then became common to write on the bulla a depiction of the tokens inside, so that the number could be checked at any point on the journey, without invalidating the bulla. It is these depictions of tokens on the outside of the bullae (pictograms) that gradually developed into writing. Eventually, the bullae were flattened out into just a tablet with the tokens shown on its surface, sufficient for most purposes.

Contracts are quite complex things, and it would have taken a long time for writing to get to the point where a contract could be fully specified in writing. However, contracts can be used even in pre-literate societies. You just need one of more witnesses to the contract, who could be called on if necessary to recount the contract. A seal would be sufficient to identify the witnesses, and just a few marks on a tablet might be enough to remind the witness of what the contract was about. For most early societies, a trusted witness was far more reliable than a few marks on a piece of clay.

A good source on bullae and writing is "Ancient Mesopotamia" by Susan Pollack.


The bullae were most likely the mechanism used by proto scribes who were middlemen conferring validity to promissory contracts between producers of value. They were kept as duplicates in the bullae, while the original tokens would circulate freely, representing value.

As you suggest, it would be used to validate a "debt" or promissory obligation between two subjects. One gives up chicken, delivers them to the "debtor", who is then obligated to redeem that "debt" by giving up a like measure of his own production. The token circulates within the economy, and when it comes back to the "debtor", he takes them to the proto-scribe to redeem that obligation, becoming fulfilling the indirect exchange of value. The token is then the medium by which the participants of this economy can exchange their own production, giving credit to the token, as it is tied to an obligation.

It could work the other way around as well, in the sense that it would be a promissory note, representing the specific goods promised by the obligor/promise/debtor that should be delivered to the bearer of the tokens on the agreed date. Once the token comes back to the original issuer (debtor), the debtor can prove that he had paid his debt, redeemed it, by delivering to the bearer what was promised.

Since there was no cuneiform script during the time these tokens circulated, there's room for speculation. But, the clay tablets which came later functioned this way, as promissory notes. Again, you can find this evidence on The Manumission channel.

The British Museum: Promissory note

YouTube: The True Origins of Money - Clay Promissory Notes

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