The Repository Códice

The Coin That Lied to Three Continents

August 20, 2026 · Runtime 13:39 · Watch on YouTube

In the sixteen thirties, bankers in Genoa and Antwerp began weighing silver bars stamped with the mark of Potosi -- and refusing them. The silver was short. It took Madrid another fifteen years to act, and by then the most trusted coin on earth was carrying a quarter less silver than it claimed, in three continents at once.

Transcript

The bankers who said no 0:00

In the banking houses of Genoa and Antwerp, in the sixteen thirties, silver bars kept arriving stamped with the mark of Potosi -- the richest mine on earth, and the most trusted metal in Europe. The bankers weighed them. They assayed them. And they began refusing them. The silver was short. It would be another fifteen years before anyone in Madrid did anything about it. The people who noticed first were not the king's officials. They were the men who counted money for a living.

This is a fraud story, and the fraud is not the strange part. Everyone in it is eventually caught, and men are executed. The strange part is in the paperwork -- what the debased coin was actually doing for Potosi, why the honest replacement was also short, and who else was doing exactly the same thing at the same time, legally, by decree, with the king's name on it.

The piece of eight 0:57

The coin was the real de a ocho. The piece of eight. By the middle of the seventeenth century it was taken in Amsterdam, in Lisbon, in Manila and in Canton -- the first thing on earth that behaved like a world currency. By royal decree of December sixteen forty-two it was to hold ninety-three parts of silver in a hundred. It did not look like much. These were cobs: cut from a bar, struck with a hammer, ragged at the edge, with the design running off the side. That was acceptable, because the value was never in the picture. It was in the metal.

What a coin actually promises 1:36

Which makes a coin a promise about weight and fineness, with somebody's name attached to it. And a lopsided lump of silver cannot be checked by eye. To know what you were holding you needed a balance and an assay -- or you needed to trust the mark. Almost everyone trusted the mark. That trust was infrastructure. It moved more cargo than any fleet did.

The mint, and who stood surety for it 2:01

The mint at Potosi was established in fifteen seventy-two. Its royal officers were the treasurer, the assayer, the smelter, the master of weights and measures, and the bailiff. They were Spanish born, they swore an oath to behave honestly, and they were bonded -- financially guaranteed -- by the leading households of the city. Hold on to that last part. The men who stood surety for the mint's honesty were the men whose fortunes came out of it. The metal itself was melted, and the blanks were cut, by indigenous draft labourers and by enslaved Africans.

One man's word 2:39

And at the centre of the building, one office. The assayer. He measures the fineness of the silver and he writes it down, and from that moment everything downstream runs on his number -- the coining, the royal fifth, the manifest, the fleet, a contract signed a year later on the other side of the world. There is no second measurement. There is one man's word, and then there is the world's money.

The ore was getting worse 3:05

By the sixteen forties the material underneath all of this was getting worse. The mines were deeper. The ore was refractory -- harder to work and poorer in silver. Labour was short, and there had been drought. The refiners had organised themselves into a guild by sixteen thirty-five, and they were sinking into debt to the silver merchants who financed them. A refiner in that position owes a fixed amount and produces less every year.

The debased coin was credit 3:34

So it was not simply theft, and this is where the archive stops agreeing with the story. Lower the silver in the alloy, and the shortfall in production disappears into the metal. The books balance. The debts get paid. The mills keep turning. Historians working the case call it an illegal financial innovation, and that is the right shape for it. The debased coin was credit. It was a loan taken out against everybody who would later hold the coin. Which has an uncomfortable consequence. For as long as it worked, the king's own revenue depended on the fraud continuing.

Names in the case 4:15

The names are known. Francisco Gomez de la Rocha, a former corregidor of Potosi and a rich silver merchant, ran the scheme through the sixteen forties along with other merchants of the city. The assayer was Juan Ramirez de Arellano. And the conditions are as damning as the men: sensitive posts inside the mint were subcontracted out, municipal and royal oversight was slack, and a whole line of mint officers and senior officials could be bought.

Four decades 4:45

It ran, in one degree or another, for about four decades. Merchants were noticing underweight and low grade pieces as early as the sixteen twenties. It was not corrected. It got worse. And after sixteen thirty-eight the debased coin stopped being a local problem and became a feature of the world's markets.

Genoa, Antwerp, and then Madrid 5:07

The bankers of Genoa and Antwerp had already started turning away bars with the Potosi stamp. Then, in sixteen forty-eight, the complaints became official -- from the kingdom of Aragon, and from Castile -- saying that pieces of eight coming out of Potosi were worth as little as five.

Seventy-five per cent 5:26

Royal trials then did the arithmetic. The coins held about seventy-five per cent of the silver they claimed. A quarter of the promise was simply absent. Not in one shipment: across years of coinage, already spent, already at sea, already in the hands of people in cities that had never heard of Potosi.

Madrid sends an inquisitor 5:47

Philip the Fourth, in the middle of yet another royal bankruptcy, sent a man. Francisco de Nestares Marin, appointed visitador general and president of the Audiencia de Charcas, the high court of the region. He was a former inquisitor. He began investigating in earnest at the end of sixteen forty-eight.

Why an inquisitor 6:09

An inquisitor looks like a strange choice for a metallurgical problem, until you notice that it was not a metallurgical problem. The assay was easy. Anyone could run it. What was hard was that the accused owned the courts, posted each other's bonds, sat on the town council and kept the books. The skill the job required was interrogation and paperwork, against people with enough local power to make both disappear. That was precisely the trade Nestares Marin had come from.

The executions 6:40

In the last weeks of sixteen forty-nine and the first weeks of sixteen fifty, the assayer Ramirez de Arellano and Gomez de la Rocha were executed. Silver merchants were executed with them. The sitting corregidor of Potosi was removed and imprisoned. And the inspection did not end there. The visita of Nestares Marin ran for about ten years.

The damage was in circulation 7:05

But executing the men does not repair the money. The coins were already gone. They were in Seville, in Amsterdam, in Manila, in the hands of people with no connection to any of this, who had taken them in good faith because of a mark on the metal. The damage was not in Potosi. It was in circulation, and it was still moving.

The rochunas are called in 7:29

So the Crown did the only thing left to do. In October sixteen fifty, Philip ordered the eight and four real pieces devalued. Then, in January sixteen fifty-two, the viceroy Garcia Sarmiento de Sotomayor issued the decree that settled it. The old debased coins -- called rochunas, after Rocha himself -- were set at six reales, for melting. Whoever was holding them, lost. The smaller denominations were left alone.

The reform coin was also short 8:00

And then there is the other line in that same decree. By then a second kind of coin existed, the rodases, named for Juan Rodriguez de Rodas -- the head assayer sent out from Spain to fix the problem. These were the reform coins. Minted under the honest man, under supervision, after the executions. The decree set the eight real rodas at seven and a half, and the four at three and three quarters. They were short as well. The state had to devalue its own corrective coinage.

What Madrid was doing at home 8:35

Which brings us to the part that is hardest to file under fraud. While Madrid was executing men in Potosi for taking silver out of the coin, Madrid was doing the same thing at home, by decree. In sixteen forty-two the government cut the face value of the Castilian copper coinage by seventy to eighty per cent. In sixteen fifty-one, short of money for the army again, it called the copper in and restamped it, quadrupling the face value. The same act. The same effect on whoever was holding the money. A different signature. The offence at Potosi was not altering the currency. It was altering it without the king's name on it.

An archive of who was answerable 9:19

It is worth being exact about what survives from this. The trial record names the corregidor, the assayer, the merchants -- men who owned things, who could be tried, and whose property could be seized. The people who melted the metal and cut the blanks, the draft labourers and the enslaved Africans who did the physical work of making the coin, appear in the mint's labour accounts. They are entered as a cost. An archive is not a record of what happened. It is a record of who was answerable, and to whom.

The fix was a design 9:52

The fix, when it finally came, was not a decree. It was a design. In sixteen fifty-two, after a run of short lived prototypes, Potosi began striking a new coin. On it: the date, the mint mark, the denomination, and the initial of the assayer who had certified it -- repeated in at least three places on the piece. The repetition was the whole point, because these were still hammered coins. They came out uneven, off centre, clipped. Put the identifying marks in three places and a bad coin can still be traced back to the man who signed for it. In March sixteen fifty-two the replacements began. Coins already in circulation were called in and countermarked. By sixteen fifty-seven the old ones were illegal to trade.

An audit trail struck into metal 10:45

Look at what that actually is. It is an audit trail, struck into metal. Money that carries, on its face, the name of the person answerable for it -- so that a failure has an address. The design is called pillars and waves: the pillars of Hercules standing in the sea. It went on to be the most widely copied coin design in the world, and it ran for more than a century. The most famous money in history is a compliance measure.

Sumatra, and a mint in Boston 11:15

The coinage was back to full weight and purity by sixteen fifty-two. The reputation was not. Twenty years later, pepper growers in Sumatra were still refusing pieces stamped with a P. And in Boston, on the twenty-seventh of May, sixteen fifty-two, the General Court of Massachusetts ordered a mint set up. The silversmith who ran it, John Hull, wrote the reason in his diary: much counterfeit coin brought into the country, and much loss accruing in that respect -- and that, he wrote, did occasion a stoppage of trade. Hull does not name Potosi, and we are not going to put the word in his mouth. What is documented is the timing, and what he did name. The coins his mint struck were brought to the English sterling standard, and they were the first coinage made in what is now the United States.

The Capitana 12:08

One last document, and this one is not on paper. On the twenty-sixth of October, sixteen fifty-four, the Capitana -- flagship of the South Sea fleet, twelve hundred tons -- struck rocks off Chanduy, on the coast of what is now Ecuador, carrying silver north from Callao to Panama. The official register listed three million pesos: two thousand two hundred and twelve ingots, two hundred and sixteen chests of coin, twenty-two boxes of worked silver. Estimates of what she was really carrying, counting what was never declared, run to ten million. She was found again in the nineteen nineties. More than five thousand coins came up, and they are transitional pieces -- sixteen forty-nine to sixteen fifty-four, the exact years of the scandal and the repair.

What could not be weighed 12:57

Which is the whole thing in one object. The coin was caught because a coin can be weighed, and the repair was to write the responsible name onto it. The cargo could not be weighed. The ship carrying the mended money was carrying something like two thirds of its silver outside the books, and nobody sent an inquisitor about that. Next time on Codice: the back door. Buenos Aires, the port Spain barely allowed to exist -- roughly two hundred unauthorised ships into the River Plate between sixteen forty-eight and seventeen oh two, Portuguese first and then Dutch -- and the silver that left Potosi without ever entering a record at all.

Description and sources

The Great Potosi Mint Fraud is usually told as a crime story: corrupt officials debase the king's coinage, a former inquisitor is sent from Madrid, and two men are executed. All of that is true. The paperwork says three stranger things.

First, the debased coin was not simply theft. It was credit. The mines were deeper and the ore was poorer, the refiners were sinking into debt to the merchants financing them, and lowering the silver in the alloy made the shortfall disappear into the metal. For as long as it worked, the Crown's own revenue depended on the fraud continuing.

Second, the reform coinage was also short. The rodases -- minted under the honest head assayer sent out from Spain, after the executions, under supervision -- were devalued by the state's own decree of January sixteen fifty-two, from eight reales to seven and a half.

Third, while Madrid was executing men in Potosi for taking silver out of the coin, Madrid was doing the same thing at home by decree: cutting the face value of Castilian copper by seventy to eighty per cent in sixteen forty-two, and calling copper in and restamping it at four times face value in sixteen fifty-one. The offence at Potosi was not altering the currency. It was altering it without the king's name on it.

And then the repair, which is the part worth keeping. In sixteen fifty-two Potosi began striking a coin carrying the date, the mint mark, the denomination and the initial of the assayer who certified it -- repeated in at least three places, so that a bad coin could be traced back to the man who signed for it even when it came out crude. That design, pillars and waves, became the most widely copied coin in the world and ran for more than a century. The most famous money in history is an audit trail.

PRINT-READY, FROM THIS CHANNEL

The Document Set, Vol. 01 — Cajamarca 1532 and Buenos Aires 1595-1680 — the documents at reading size, with author, date, archive and licence

https://therepository.gumroad.com/l/document-set

SOURCES — every image in this video is a public-domain document.

Each plate below is listed with its author, date, holding archive and licence.

Bonaventura Peeters the Elder — between 1600 and 1649 | Wikimedia Commons | Public domain
Marinus van Reymerswaele — 1540 | Wikimedia Commons | Public domain
Cramer, Johann Andreas — 1764 | Wikimedia Commons | Public domain
8 Reales, Bolivia, 1647, National Museum of American History | Wikimedia Commons | CC0
Philip IV of Spain, silver florin, Brabant, 1623 | Wikimedia Commons | Public domain
Erasmus de Bie — 17th century | Wikimedia Commons | Public domain
Farnham Bishop | Wikimedia Commons | Public domain
Marinus van Reymerswaele — first half of the 16th century | Wikimedia Commons | Public domain
Marinus van Reymerswaele — 16th century | Wikimedia Commons | CC0
Gaspar Miguel de Berrio — 1758 | Wikimedia Commons | CC0
Georgius Agricola — 1556 | Wikimedia Commons | Public domain
Georg Agricola — 1556 | Wikimedia Commons | Public domain
Georg Agricola — 1556 | Wikimedia Commons | Public domain
Georgius Agricola — published 1657 | Wikimedia Commons | Public domain
Marinus van Reymerswaele — 1540 | Wikimedia Commons | Public domain
View of Seville, circa 1660 | Wikimedia Commons | Public domain

... and 24 more plates, each credited on screen in the video and listed in this project's manifest.

This video also contains 4 synthetic illustration(s), used only for moments no archive covers (an empty square, an empty road). They are generated with Stable Diffusion XL and are marked as synthetic content on YouTube. No identifiable historical person is reconstructed.

Codice is a history channel built from the archive. Every image is a real document in the public domain, credited above.

Written and produced with archival research; sources are listed so you can check them.

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