If you have spent any time playing Kingdom Come: Deliverance, or its 2025 sequel, you will already be familiar with the groschen. Every sword you sharpened, every innkeeper you bribed, every horse you bartered for was measured in this small, dense, silver coin. What the game captures, perhaps better than any other, is that the groschen was not just currency. It was trust, made solid in silver.

But where did it come from? And why, of all the coins circulating in medieval Europe, did this one become the dominant money of an entire continent for two and a half centuries?

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A Kingdom Beneath the Mountains

To understand the Prague Groschen, you first have to understand Bohemia, and the extraordinary geological luck that lay beneath it.

By the late thirteenth century, the Kingdom of Bohemia occupied the heart of Central Europe, a fertile highland basin ringed by mountains and rich farmland. Its kings were electors of the Holy Roman Empire, some of the most powerful monarchs on the continent. But Bohemia's real advantage was underground. In 1298, silver was discovered near a small town called Kutná Hora, roughly fifty kilometres east of Prague. What followed was one of the great mineral windfalls of the medieval world.

At its peak, between 1300 and 1340, the mines at Kutná Hora may have produced as much as twenty tons of silver a year, an output that made Bohemia, almost overnight, one of the wealthiest states in Europe. The king who inherited this fortune, Wenceslaus II, understood exactly what it meant.

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The Reform

Wenceslaus II was not simply lucky. He was shrewd. Rather than mint the silver into the existing coinage: thin, lightweight denarii that were easily debased and wildly inconsistent across regions, he commissioned an entirely new coin.

He brought in Gozzius of Orvieto, an Italian lawyer and financial expert, to draft both a new mining code (Ius regale montanorum) and a reformed monetary system. The result, struck for the first time in April 1300, was the Prague Groschen.

The name itself tells you what made it remarkable. Grossus is Latin for "thick", and that is precisely what it was. Against the flimsy denarii that had passed for coinage across the region, the Prague Groschen was a substantial thing: roughly 3.8 grams of silver at a fineness of over 93%. It was heavier, purer, and more consistent than almost anything else in circulation.

The design was equally deliberate. On the obverse, a stylised royal crown surrounded by the king's name and title in two concentric rings, DEI GRATIA REX BOEMIE, "By the grace of God, King of Bohemia." On the reverse, the Bohemian lion, striding and crowned, encircled by the coin's own proud declaration: GROSSI PRAGENSES. Prague groschen. The coin named itself.

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The Mint at Kutná Hora

The groschen was not struck in Prague, despite its name. The mint was established at Kutná Hora itself — logical enough, given that the silver was already there. The facility, later known as the Italian Court (Vlašský dvůr) in honour of the Italian experts who shaped the reform, became the economic engine of the Bohemian crown.

At its height, the Italian Court was producing up to 1.7 million coins a year. Unskilled labourers across Bohemia typically earned one groschen a day; a skilled craftsman might earn two. A coin struck in such volume, at such consistent quality, had enormous reach — not just within Bohemia, but across borders.

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An International Currency

What happened next is what elevates the Prague Groschen from a successful regional coin to a genuinely historic one. Because it was reliable, constant in weight, constant in design, constant in silver content, it spread.

Merchants in Poland, Hungary, Lithuania, and the German lands began accepting it not merely as foreign coinage but as a preferred standard. In major trade documents of the era, large sums were denominated in sexagena of Prague groschen, "kopa," meaning sixty, a unit so widely understood it appears in international treaties, including the Peace of Thorn in 1411.

Other rulers noticed. The Meissen groschen, introduced around 1338, was modelled directly on the Prague standard. The Kraków grosz, struck under Casimir III of Poland from 1367, similarly adopted its weight and fineness. The Prague Groschen did not merely circulate across Central Europe, it set the template.

For a time, it served the role in Central and Eastern Europe that the pound sterling or the dollar has played in more recent centuries: not just a coin, but a benchmark.

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The Long Decline

Nothing so successful lasts unchanged. The pressures that eroded the groschen were the same ones that have undermined currency throughout history: war, fiscal strain, and the temptation to get more coins from the same weight of silver.

During the reign of Wenceslaus IV (1378–1419), the coin was debased four times. By 1403, the silver content had fallen from its original 3.65 grams to 1.75 grams of pure silver, less than half. By 1407 it had fallen further still. The coin that merchants had trusted precisely because of its consistency was quietly becoming a different object, wearing the same face.

By the time Ferdinand I discontinued minting in 1547, the groschen weighed barely two grams. The discovery of rich new silver deposits at Jáchymov (Joachimsthal) had already introduced its replacement, the Tolar, a large, heavy silver coin whose name would, by a long journey through German and Dutch, eventually give the English language its word for the dollar.

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What the Coin Tells Us

The Prague Groschen endured for almost two hundred and fifty years. That is a remarkable lifespan for any currency. Its design, crown on one face, lion on the other, remained essentially unchanged from 1300 to 1547, even as the silver within it quietly shrank. There is something almost poignant in that stability of image against a background of gradual debasement: the appearance of reliability outlasting the reality.

For a coin collector or numismatist, the groschen offers a long and legible history. Early issues, struck under Wenceslaus II with their full silver content and crisp detail, are among the finest products of medieval Central European minting. Later issues tell a different story, broader, lighter, the legends sometimes cruder, but no less historically rich for that.

And for anyone who has ever wondered, while navigating the muddy roads of fifteenth-century Bohemia in a video game, whether the money in their purse had any basis in reality: it did. The Prague Groschen was as real as the silver mines that made it possible, as real as the kingdom that grew wealthy on it, and as real as the slow, inevitable decline that all currencies, however well-designed, eventually face.