Roman coins come in all sizes and shapes, we know, and of these among the most controversial aren't really coins at all. Relatively rare, a minor of class of semi-anonymous coinage carries, on the one side, a large Roman numeral and on the other (often) couples making love in explicit poses seemingly plucked straight out of the pages of the Kama Sutra. Probably no civilization as a whole is identified with raw sexuality as much as that of the Romans with surviving art pieces freely illustrated with the business of the flesh. Historians, tabloid gossipers and pretty much anyone with the ability to write back then delighted in describing the prurient perversions of others be they highborn or commoner. Yet its coinage is largely chaste to a fault. So what gives then? Modern historians, often constrained within the bounds of propriety, have struggled to reconcile the significance of these naughty bits. Ignoring the elephant in the room, some have unconvincingly proffered their use as gaming tokens or event passes. Sooner or later the elephant has to be acknowleged and the baser use of facilitating the sex trade is given a chance.
Despite the halfhearted sanitizing attempt this much is hardly controversial. What's the deal with the numbers though? Common thinking, likely born of an inspired moment in a smoky bar attended by off-duty historians, is that the number must tie into the featured act so that, in effect, the number becomes its price.
While no one without a time machine can say for sure, just using logic it really strains the mind that the token pictorial had anything whatever to do with the service the client was paying for! Prostitution the world over is a simple business that changes very little in its basics and, lacking anything weighty to the contrary, one must assume that these basics remained more or less the same across the ages as well. It is not practical for a big, modern brothel to have its staff mediate transactions between the sex worker and the client. It kills the vibe to say the least. It is much more efficient for the house to leave the particulars up to the individuals and charge admission or charge the prostitute for use of the facilities - or both. While management has an easier time regulating income this still leaves the prostitute without an easy means to get paid for her services. If the john pays cash where does she put it without it becoming a security risk? Also, if the john must pay for services repeatedly with his hard-earned coin, will he spend as freely?
Casinos pondered the practical - and psychological - implications long ago and came up with the devilishly effective solution of tokenry. Useful only within the confines of its facility was both a strong disincentive to theft as well as providing a subtly uninhibiting effect when it came time to part with them. A brothel, which like a casino sells vice as its product, is the perfect analogy model and the two share identical problems and goals regarding discretion, security control and the fostering of an artificial environment conducive to carefree spending. Viewed in this light the raison d'etre for the numbers becomes clear: since the brothel is unable to issue plastic chips of varying colors to identify their value the numbers are the most plausible alternative. They weren't the price, they were the value. And this value could have been arbitrary and non-linear. Numbers as high as XVI (16, for those of you unfamiliar with Latin number encoding) have been recorded but there is no indication whether that was the high- or low-mark or whether these values were preset at all. For all we know that VI in the image to left could have bought you a half hour of hanky panky with that new hottie slave just in from Persia. Maybe it was just the room number. In the end it's irrelevant for it could mean anything including, yes, even the literal cost for such and such act. But, supposing for the sake of simplicity the numerals represented increasing worth, the "big chips" could have been internally broken down into fractions as needed. To sum, there is no doubt that within the brothel some services cost more than others (in fact, food, accessories and non-sexual services and items likely were sold on the premises too) but my point is that it's incredibly naive to think that there was a direct and unyielding correlation between the scene depicted and its cost.
Seeing as how the spintriae were most likely brothel tokens, and additionally that the numbers did represent a value but not a specific cost, leaves us with a final question. Why if this system was so efficient did the spintriae seem to have been issued for only a few years? In other words, why was its implementation not widely institutionalized throughout the Roman age? This answer is troublingly elusive to me. Prostitution was by all reports an essential component of the economy and if the innovation of tokens made this particular business run so much smoother it stands to reason that it should have caught on. Certainly there is the possibility that the experiment failed for any number of reasons and it all reverted back to being handled in cash but when profits and security are at stake I resist such a facile explanation given what I know of human nature. Perhaps the business itself changed so that prostitution leaned ever more towards a back-to-basics "pimps and hoes" streetside tricking (cheaper, less overhead). Or perhaps there was some other as-yet unseen factor that made the innovation unsatisfactory in the end. Maybe the fickle hand of imperial policy played a part.
Personally, after dicing away at the problem with my trusty occam's razor, I've come to the conclusion that the most likely answer is not that the use of tokens went away at all but rather that it was taken to its next logical step in evolution. Couldn't it be the case that the tokens were simply abandoned as too costly when some other stand-in could have been employed just as well? A brothel need not have required the commissioning of expensive metal trinkets when, say, a dyed rabbit's foot or a wooden figurine of Pudicitia (har, har) could have done the job just as efficiently.
That's Roman ingenuity at work for ya.