Copyright � 2010 by Shane Tourtellotte First published in Analog Science Fiction and Fact December 2010 2010 Analog Analytical Laboratory winner, Best Fact Article Time travel is a favorite topic for science fiction, but one that, by its nature, resists the kind of rigorous factual analysis its readers and writers would put into orbital dynamics or genetic recombination. Still, there are practical issues one must tackle if visiting another era. Language is one, a topic covered admirably in L. Sprague de Camp's "Language for Time Travelers."1 Another is the matter of money. Seldom in SF do we see a time-traveler arrive in a past society with the financial resources needed to support himself for any length of time. Many stories ignore the matter altogether; others have the traveler fall in with some benefactor; in others the time travel was unplanned and precipitous. A protagonist who takes intelligent steps to fund his sojourn is uncommon. For a reading audience that likes rigorous storytelling, this cannot really satisfy. It would be simple and convenient to posit a filthy rich time-traveler who can overcome this problem by brute force. Too simple, too convenient. Suppose, instead, that the expenses of building your time machine have tapped you out, that you have a relative pittance left to back your trip to Agincourt or Marathon or the court of Cleopatra. How can you maximize your limited budget to support your adventure in the past? This essay will provide some answers. To illustrate various principles, I will use the specific example of traveling to the early Roman Empire2. The Augustan Era, along with being a popular period likely to draw a time-traveler's interest, provides excellent examples on several points. The methodology presented should help you cope with any other past period you choose to visit. So, our first question arises: how to get the money you'll need in the past? Heavy Metal Ideally, you would have a stash of the currency used in the period you'll be visiting. Realistically, your coin collection probably isn't that extensive, and buying up genuine ancient coins would be overly expensive due to scarcity and other factors. You might contemplate counterfeiting period currency, but besides still being an expensive venture, it would be highly risky both in the present and the past3. Go back more than a few centuries, though, and your options widen. People will accept more than standardized, state-produced currency. Precious metals, gold and silver, will pass well, as long as the recipient can be reasonably sure of weight and purity. Taking back bulk gold and silver will be much more efficient than buying period gold or silver coinage with the same money. If need be, you can purchase period currency with your metals in the past, at a much more lenient premium than at a coin dealer or an on-line auction today. But of your two main options, gold and silver, which will get you further in the past? The value ratio of gold to silver was remarkably steady for most of human history. From far antiquity to the start of the 16th century, an ounce of gold was roughly 12 times more valuable than an ounce of silver. There were local fluctuations, such as when Rome's access to silver was cut off during the Second Punic War, but global systemic movements were glacial. The ratio shifted when Spain's silver mines in South America began producing, depressing prices for silver and moving the ratio to between 15 and 16 to 1. The greater dislocation came in the 19th century, when the Western nations, led by Great Britain, abandoned silver standards for their currencies in favor of gold. Deprived of this support for its value, silver fell, especially compared to gold, which gained that very support. The gold-silver ratio has been increasingly volatile for the last century and a half. Through many economic upheavals, including the global abandonment of the gold standard, the ratio has soared almost to 100-1, and plummeted back to 14-1, almost as low as the ancient norm. (See Chart 1.) We sit between the extremes as I write, with gold about 65 times as valuable as silver4. If you are going back to ancient Rome - or to virtually any time before the American Civil War - silver is more cost-efficient, getting you roughly five times the value for the present-day expenditure. The problem is that silver is far less mass-efficient. Walk any distance with sixty pounds of silver on your back, and you may wish you had paid that 400% premium for a nice, portable five pounds of gold that will be worth just as much to the locals. Silver is at best a partial solution for the budget time-traveler. Some of your assets should go into that, for solid value and easy convertibility. The rest would be better used in something a little more speculative, but capable of producing far greater returns: trade goods. The Wealth of Bygone Nations If you're going to be a cross-time trader, you need to keep economic basics in mind. The most important in your situation is: know your market. This means knowing what the locals use as money, in all its denominations, knowing your customers' likes and habits, and knowing local price conditions. All of these require historical research, and for the latter two, one soon comes to appreciate how patchy our knowledge of quotidian matters from the distant past really is, even in such a famous nation as ancient Rome. Famous writers whose works have reached us do often expound on cultural matters of what products are in vogue, but dry price listings are far less common. And who can blame them? If a Jane Austen novel digressed for five pages on the prices at a local market, you'd yawn and skip ahead to the next ball. Some price listings do reach us from the Roman Empire. The Emperor Diocletian, reigning around A.D. 300, attempted to control rampant inflation with mandatory price controls, and the list of these maximum prices survives5. Cato the Elder covers prices related to farming in his De Agri Cultura, but these have a necessarily limited application to us. Our best and broadest source comes from the closest thing Rome produced to a modern scientist: Pliny the Elder. Pliny's Naturalis Historia (Natural History), published soon before his death in A.D. 79, can plausibly be called the first encyclopedia. Among his exhaustive listings of natural facts are a number of prices for botanical, mineralogical, and other items useful to a time-trader. Pliny did make his share of errors in trying to encapsulate the known Roman world, but taken with care and some fact-checking, his Natural History is invaluable6. Your dealings will also have to follow the most famous economic maxim: buy low, sell high. One part of this will be where you do your buying and selling. Large cities will create pricing premiums, in the past as today: bread, for example, cost twice as much in ancient Rome as in the countryside. The greater application is in finding goods that are cheap for you, but not only expensive for the buyers, but still things they will want to purchase at those prices. Your advantage as a time-traveler here, in the added knowledge you possess, is key. You will know which items, mundane and plentiful for you, are captivating and rare for your customers. Rarity is a crucial point. The best guarantor of high prices is scarcity: even a mediocre commodity can fetch high prices if it is rare enough to gain cachet as a luxury item. And the best creator of scarcity, across most of human history, is great distance between a good's source and its market. We easily forget this today, when it can be more economical to import even the cheapest items from ten thousand miles away than to manufacture them locally. But reduce today's web of global shipping to a few tenuous trade routes stretching across mountains, deserts, or oceans, and prices can spiral to dizzying heights. Historically, distance is a strong price multiplier, a fact we will have occasion to exploit. Beyond this theoretical grounding, there are practical concerns. As mentioned with silver, high value is a mixed blessing if it comes with back-breaking weight. Ideally, you want a high ratio of value to mass and bulk. Also, you want something you can convert easily into money or property. A hundred-dollar bill is legal tender today, but you'll have trouble spending it at the local kids' lemonade stand. And no matter how valuable your "Sunflowers" by van Gogh is, the faster you need to sell it, the smaller the fraction of its worth you'll get. Similar troubles will arise if you try to conduct business in the past with a ten-pound gold ingot or a five-carat emerald. So we have a concise set of rules. We want compact trade goods, cheap today but dear in the past, with enough demand to support whatever we wish to sell. Our value baseline is silver, which was set by Caesar Augustus's monetary reforms as 84 denarii per libra7. Buying a denarius's weight of silver costs us roughly $2.25 today (by the price given in footnote 4). If your trade good doesn't fetch more money per pound than this in the past, you're likely better off taking back silver instead. So what goods are ideal for our temporal argonaut setting down in ancient Rome? The Spice Must Flow Spices and aromatics from the Orient were popular in Rome of the Augustan Age and later. Imported spices went into food, wine, and perfume in limitless combinations and voracious quantities. Pliny the Elder lamented that twenty-five million denarii a year went East to buy such goods from India at enormous mark-ups8. Here is a tremendous - but elusive - opportunity. Pepper is famed for its value to Romans: when Alaric the Visigoth besieged Rome in A.D. 408, part of the ransom he demanded to spare the city was three thousand pounds of pepper9. Its unit price, however, is disappointing. Pliny recorded that black pepper sold for a mere four denarii per libra, and long pepper, the most expensive variety, came in at fifteen d/lb. Buying pepper today to sell at those prices is a worse bargain than silver. Frankincense and myrrh, aromatics famed from the New Testament, seem to hold promise, but again Pliny dashes that hope. Top quality frankincense brings only 6 d/lb, he says, and myrrh tops out at 16 d/lb. Pliny never gives a price for saffron, but does say it is the commodity most often falsified, so there was plenty of perceived value in passing off fakes. However, the reason saffron is so obvious a luxury item to us is that it is so expensive today. The highest quality saffron goes for around ten dollars a gram - and Romans paid attention to quality, so it's a poor idea to try scraping by with cheap stuff. Odds are low that saffron would be worth so much more to Romans to justify the expense, not to mention the risk that buyers will think this suspicious stranger is trying to pass off bogus saffron. Pliny's information on cinnamon is interesting, partly because it covers several different plants. The foodstuff generally sold in America today as cinnamon is actually cassia. Pliny says the highest quality of cassia will sell for fifty denarii per libra, and the lowest at five: not up to our requirements. He gives a more promising price for daphnoides, or isocinnamon, at three hundred denarii a libra. The trouble here is that we are not certain what plant Pliny meant here, a variety of cassia or another plant altogether. We are more sure of the identity of Pliny's true cinnamon, as being Cinnamomum zeylanicum, the cinnamon tree native to Sri Lanka. The extant price he quotes for it is a disappointing ten d/lb, useless for our purposes. But then he adds this fascinating line: "The price of it was formerly as much as a thousand denarii per pound ..."10 What happened to bring the price of cinnamon down by ninety-nine percent, in a timeframe apparently within Pliny's living memory? The answer seems to have been a revolution in navigation, or at least the uncovering of a trade secret, by the Romans. Originally, Roman ships sailing from Egypt to India would have had to hug the coastlines of Arabia and Persia, rather than risk a long open-water crossing of the Arabian Sea11. This meant a round-trip time of three years to deliver one shipment of goods from India. Few Romans cared to take the time and risks, and trade with the East was left in the hands of Arabian middle-men, who charged immense premiums. (Pliny mentions them scornfully in connection to the pepper trade, opining that they sell pepper to Romans for a hundred times what they paid for it in India.) Some time roughly in the fifth decade A.D., a Greek sailor named Hippalus discovered the course and pattern of monsoon winds in the Arabian Sea12. Winds blew from the southwest from April to October, then from the northeast the rest of the year. Sailing from the Gulf of Aden to the Indian coast could now be accomplished in forty days, and the round-trip time from Egypt to India was slashed to one year. It still required daring to cross the Arabian Sea, trusting to the winds and primitive navigation, but Roman sailors now liked their odds much more, especially considering the very high reward. With the Arabian middle-men cut out, prices tumbled dramatically. This was good news for the Romans of Pliny's era - and even better for the time-traveler going back before that time. True cinnamon may sell today for roughly a hundred dollars a pound (in stick form, far preferred by Romans), but re-selling it for a thousand denarii per libra is an excellent profit. That's twenty times better than silver, in a commodity worth as many denarii per ounce as silver is per pound. And other spices now gain in retrospect. Pepper may have been worth far more in Augustus' time than in Pliny's, worth a calculated risk. Indeed, anything coming from India - or farther east, like China - is a plausible trading item in the time-traveler's cache, a fact we will return to later. Pearls of Great Price Precious stones are an obvious candidate for cross-time trading. They're very small and light, pack lots of value into their volumes, and Romans of this period were hungry for them. Finding an ideal trade item among them, however, is again tricky. Diamond, Pliny said, "possesses the greatest value, not only among the precious stones, but of all human possessions."13 Romans prized it not merely for display, but for supposed medical benefits, to neutralize poison and cure mental disruptions. They knew only raw diamonds, as diamond cutting and polishing were developments far in their future: one can only speculate how much more they would pay for our modern multi-faceted marvels. The practical trouble here is that we esteem diamonds, if anything, even more highly. They're a by-word for excellence and luxury, a near-mandatory component of our matrimonial customs (both before and after), and an effective monopoly keeps their prices even higher than what they would naturally fetch. At best, trading diamonds would be an expensive speculation, with serious risk of losing value in the bargain. Emeralds, also noted by Pliny as much beloved, carry the same drawback: we find them similarly valuable. Rubies, not quite as alluring to Romans, are even more costly per carat to us than diamonds. Our best hope is in finding a stone that is commoner to us than it was to Romans. Opals show some promise here, as large finds in Australia have expanded that market14. But we can do better - much better, in fact - with the stone Pliny placed only behind diamond, and ahead of emerald, in the esteem of Romans: pearls. Roman literature amply records the great worth they placed on pearls. Lollia Paulina, one of the wives of the Emperor Caligula, is reported to have worn ten million denarii of pearls and emeralds at a time. The historian Suetonius says that Julius Caesar paid 1.5 million denarii for a single pearl he gave to his mistress Servilia. And Cleopatra herself is fabled to have dissolved and drunk a pearl worth 2.5 million denarii to impress Mark Antony with her immense wealth (which she could put behind his military and political ambitions). Even if, as is quite possible, all three of these tales are exaggerated or wholly fictitious, they speak clearly to how highly Romans valued pearls. Here we gain a clear advantage. Though Romans did raise oysters for eating, they never conceived of helping those oysters produce pearls15. Our pearl culturing industry gives us much cheaper pearls for the size and quality. To give an example, in 1917 the famed jeweler Pierre Cartier bought a Fifth Avenue mansion in Manhattan for a double-strand of matched pearls worth $1 million16. Forty years later, after pearl culture was well established, the same pearl necklace sold at auction for a mere $157,000. Due to intervening inflation, this drop is even more precipitous than the apparent 84%. Do not try to pass off fake (as distinct from cultured or natural) pearls for a little extra profit. Romans were discriminating and attentive in their luxuries, and will spot a fake pearl easily, to your severe inconvenience. That said, cultured pearls promise high profits in a small package, even if the initial expenditure may be substantial. Other Ways of Showing Off Other luxury items offer excellent prospects, two of them coming again from the fabulous Orient that captivated the Roman imagination. Silks first reached Roman attention in the first century B.C., with imports from China via the Parthians17. Silk's charm became so popular that the Senate passed several sumptuary restrictions or outright bans on silk clothing, both to stanch the flow of money east and to fight the decadence of such sheer and revealing material. These edicts had the effect you would expect - silk became even more popular - so you will be able to sell your silk with little problem, and at a good profit. Raw silk is recommended, though: Romans liked to blend their silk with linen for a while, before the decadence truly set in during the first century A.D. and pure silk garments came into vogue. Another potential prize is porcelain. History tells of the Murrine cups imported at immense cost from the East, and scholars think this may have been porcelain. The Emperor Nero paid a quarter-million denarii for a single Murrine cup. You oughtn't count on doing that well yourself, and the scholars may be wrong, but taking back a good-quality porcelain cup in hopes of finding a rich buyer is a sound calculated risk. Closer to home, dyes, and specifically the famed Tyrian purple, have potential. The Romans could only extract purple dye from certain eastern Mediterranean sea snails, in a process so inefficient that hundreds of thousands of these snails perished to produce one ounce of dye. The purple dye was worth its weight in silver in the fourth century B.C., and by the second century A.D., when Rome provided much heightened demand, Pliny the Younger reported it fetched a thousand d/lb, roughly worth its weight in gold. Bringing back modern artificial dye, far less costly to you, is a good profit opportunity, though with caveats. Roman law tightly restricted who was allowed to wear purple-dyed clothing, so your market is limited. Also, we are not certain of the shade that was Tyrian purple, since ancient records conflict, though it's possible a range of colors would have passed as such. An artificial dye might also arouse suspicions with people used to handling the natural dye18. Purple dye is no sure thing, but it's another good risk. All the Modern Conveniences So far, all our proposed trade commodities have been things the Romans had for themselves. But what's the fun in time-traveling if you can't sell the proverbial Sherman tank to Julius Caesar? This essay won't speak to fun, but profit isn't as easy as you might think. The problem with many modern devices is that they need the infrastructure of modern society in order to keep functioning. A revolver will need fresh supplies of bullets; a pocket computer will need new batteries; a car needs refined fuel, and will soon fail if you try to skate by on something cruder. Without this support, you have short-lived curiosities, with a correspondingly small market. You can try passing them off as something more durable only if you plan on skipping town fast. Modern materials like rubber or plastic could impress Roman customers, but they have long experience working with other materials, and may think the practical gains from yours merely incremental. Your best option could be to position them as novelties, to gain the luxury premium. This would offset the problem of plastic and rubber being bulky, again limiting how much you can bring along. As before, something light and valuable is your best bet. Medicines and antibiotics fit, and provide benefits the Romans could produce for themselves sporadically at best. Many medicines, though, will take days to show clear effects (in, say, fighting a wound infection or reversing a vitamin deficiency). You will want something immediate, if you want to prove its worth quickly for sale. Aspirin and other analgesics are good - pack some - but there is something better still: erectile drugs. Roman literature, like many others, is full of men going to all manner of extremes in hopes of bestirring themselves19. Find the right rich man, give him a single pill as proof of concept, and you can virtually name your price for the rest. Yes, it's exploitative, but you'll be giving actual value for money, which is more than most of the charlatans leeching off his troubles will manage. Turning a Profit Most of this essay has concerned acquiring the most money in the past for the least expenditure in the present. But many time-travelers intend, or at least hope, to return eventually to their present. For those on a budget, the appeal of bringing something back that will repay all their outlays, and more, is naturally strong. Our question is now reversed: what can a time-traveler buy in ancient Rome that will be worth the most in the present? Artwork is a temptation, but in most cases carries the same strong disadvantage. Whether it's a marble or bronze sculpture, a mosaic, or a mural painting (Romans did most of their paintings on walls), the artwork in question will be heavy, bulky, and very difficult to transport, the same problem we guarded against in bringing trade goods to Rome. One exception is Roman painting done on wood: we know it was done, but no examples have survived two millennia20. Any example of that would be unique, and valued as such, and could reasonably be carried by an enterprising time-traveler. Another possibility, one that would make many scholars ache with yearning, is bringing back lost literature. Many Roman writers are known to us only through reputation, with nothing but fragments of their writings surviving. Others are missing parts of their canon, even pieces of individual works. Perhaps most tantalizing, Roman libraries would be a conduit to the great Greek playwrights - Aeschylus, Sophocles, Euripides, Aristophanes - all of whom have many lost plays. (See Table 1.) A moderate expenditure for a light and portable scroll is virtually a no-lose proposition. Table 1: Surviving works of ancient Greek playwrights Playwright Plays Written Plays Surviving In Whole Plays Surviving In Fragments Aeschylus 80-97 6 70+ Aristophanes 40 11 11 Euripides 92 19 17 Sophocles 123 7 25+

How remunerative these lost works would be is debatable. A lost Sophoclean tragedy would draw bids not from Hollywood studios, but from Classics departments at universities with much less money to offer. Quality is also a concern: the works most likely to vanish from history would probably be the ones thought least worth copying and preserving. But tastes do change: plays and essays the Romans would have shrugged at might speak much better to people of today21. The difference for our time-traveler would probably be between a merely great investment and a bonanza. And for anyone wary of yet more speculations, there's a far simpler method for making money: spend your silver to buy gold. It will be worth five times as much back in the present, and it will probably be a while before copycat time-travelers glut the modern gold market and depress the price. Conclusion I hope this article has shown, engagingly and accurately, the principles for stretching your time-traveling dollar its furthest in bygone ages and societies. For certain practical reasons, the examples given are speculative, and your experiences may vary. I heartily encourage anyone who does travel into the past to correct me on any points where they find I was in error, ideally in this magazine. You will have keen and enthusiastic readers, myself first among them. Footnotes: Astounding Science Fiction (now Analog), July 1938. Research for my story "The Man from Downstream" directly inspired this essay. Counterfeiting carries heavy enough prison terms today, but in many nations of the past, counterfeiting was a capital crime - even in the early United States! There are enough perils in time-travel without adding this one to the list. Based on London spot closing values on July 16, 2010: gold at $1,189.25/oz and silver at $18.25/oz, giving a ratio of 65.16. For the historical record, Diocletian's price controls were ineffective against inflation. The Natural History used primarily in this essay is the annotated 1855 translation by John Bostock and H.T. Riley, available online at http://www.perseus.tufts.edu/hopper. The denarius was the main unit of Roman currency during the late Republic and early Empire. It was a silver coin weighing about four grams (until Nero debased silver currency). The libra was the Roman pound, roughly equal to three-quarters of an avoirdupois pound, or one-third of a kilogram. Natural History, book 6, chapter 26. The Senate gave Alaric the pepper, along with the gold, silver, silk, and dyed hides he demanded. Then Alaric returned the next year for another siege, and sacked Rome in 410. Moral: giving away your pepper doesn't solve anything. Natural History, book 12, chapter 43. The Romans, never the greatest of navigators, did the same coastline hugging when sailing the Mediterranean. This is where we derive the term "coasting" to mean slow, unforced movement. There is great uncertainty in the historical record regarding Hippalus. Postulated dates for his discovery stretch as far back as the second century B.C., and some claim he only discovered routes to specific trade ports, the monsoon pattern being known long before - and known for centuries as the Hypalus! I hold with the oftener-cited later dates because the cause and effect of lower prices following the discovery of an easier trade route is natural and logical. As to Hippalus/Hypalus, I suspect the Hypalus winds gave their name as an honorific (cf. Scipio Africanus) to the man who harnessed their use. Natural History, book 27, chapter 15. One hazelnut-sized opal set in a ring was worth half a million denarii. When its owner wouldn't sell it to Mark Antony for a twentieth of that price, he was condemned to death and had to flee for the outer provinces. Pearl culture was only invented at the end of the 19th century, and first applied on a commercial scale in 1916. Plus $100 in cash. Silk became so intertwined with China in the Roman mind that our word for the raising of silkworms, sericulture, derives from the early Roman name for China, Seres. For one matter, the Murex snails created an awful stink when processed for dye: the dye may have carried some of this tell-tale smell. Analog readers will recall a related situation in Barry Longyear's 2009 serial Turning the Grain, in which the analgesic caused the need for a potency therapy. Wood painting wasn't merely a Roman method: Leonardo da Vinci painted Mona Lisa on wood, not canvas. In Shakespeare's lifetime, for instance, his poem Venus and Adonis was more popular than his Sonnets, and his most popular play, according to contemporary playwright Ben Jonson, was Titus Andronicus. Back to Top Read "The Man From Downstream" Back to Home Page