World’s Oldest Known Coin Mint Unearthed in China

World’s Oldest Known Coin Mint Unearthed in China

Archaeologists in China have discovered a foundry that dates back to between 640 and 550 BCE. In addition to tools, ornaments, and spare parts, the foundry produced standardised coins, making it the oldest known mint in the archaeological record.

They don’t look like conventional coins, but these artifacts, called hollow-handle spade coins, served that very purpose thousands of years ago. New research published in Antiquity details the discovery of an ancient mint that manufactured this irregularly shaped currency between 640 and 500 BCE. Archaeologist Hao Zhao from Zhengzhou University, China, led the new research.

This date range is significant, as the foundry, located in China’s Henan Province, is now the oldest known mint on record. As such, it’s shedding new light on the origin of coins — a paradigm-altering innovation that changed the course of human history.

And that’s hardly hyperbole. The “availability of coinage significantly reshaped economic and social institutions, both materially and ideologically,” and, in addition to promoting commercial exchange, coins also “ provided human societies with new ways to evaluate wealth, prestige and power,” write the archaeologists in the new study. But as they point out, the “origin and early history” of coins and the “social dynamics under which they were developed…remain controversial.”

Aerial view of the ancient foundry.  (Image: Hao Zhao)
Aerial view of the ancient foundry. (Image: Hao Zhao)

The earliest coins date back to China, Lydia (Western Asia Minor), and India. Ancient mints associated with these locations date back to roughly the same time period, but none have been radiocarbon dated. Interestingly, no minting site from Anatolia or Ancient Greece has been found to exist before 400 BCE. The newly discovered foundry, found in the rural township of Guanzhuang, was radiocarbon dated, making it the “world’s oldest-known, securely dated minting site,” according to the study.

Guanzhuang was a city and important administrative centre of the state of Zheng, a regional power that ruled prior to the rise of Imperial China. The city existed from around 800 BCE to 450 BCE, and its inhabitants are known to have used spade coins.

The large Guanzhuang foundry, located in an industrial area at the outskirts of the city, was highly organised and capable of mass-producing copper items. The new paper documents the discovery of many items associated with the foundry, including dozens of used and unused coin molds, coin fragments and metal debris, thousands of pits filled with production waste, and more than 6,000 clay molds used to produce various types of bronze artifacts, including ritual vessels used by the elite members of society, weapons, chariot fittings, musical instruments, ornaments, tools, and of course, the spade coins. Other recovered artifacts associated with the foundry include crucibles, ladles, charcoal, and furnace fragments. The foundry was first put into service around 770 BCE, but it wasn’t used to manufacture coins until 640 BCE.

Discarded core heads found at the site.  (Image: H. Zhao et al., 2021/Antiquity)
Discarded core heads found at the site. (Image: H. Zhao et al., 2021/Antiquity)

“The minting techniques employed at Guanzhuang are characterised by batch production and a high degree of standardisation and quality control, indicating that the production of spade coins was not a small-scale, sporadic experiment, but rather a well-planned and organised process in the heartland of the Central Plains of China,” according to the study.

Importantly, two spade coins were recovered from the Guanzhuang foundry. Analysis showed them to be made primarily from copper, with tin and lead comprising the remaining elements. They were originally 14 centimeters tall and 6 centimeters wide, as revealed by the molds, though the two recovered coins were slightly broken, making them 11 cm tall.

Hollow-handle spade coins, or kongshoubu, were deliberate attempts to imitate another useful item: metal spades used in agriculture and gardening. But these coins, with their thin blade and small size, suggest no other practical or utilitarian purpose. Over time, these coins became more sophisticated, with inscriptions applied to them to signify value. Spade coins were used for hundreds of years until First Emperor Qin abolished them in 221 BCE.

Diagram showing how the spade coins were manufactured.  (Graphic: H. Zhao et al., 2021/Antiquity)
Diagram showing how the spade coins were manufactured. (Graphic: H. Zhao et al., 2021/Antiquity)

The location of the foundry is notable, in that it could tell us something about the origin of coins. Some archaeologists and anthropologists argue that merchants first came up with the idea of using metal currency. But the location of the site, near gates leading to the administrative sections of the inner city, suggests state officials were involved. The “discovery of the Guanzhuang mint reminds us to consider the role of the political authorities in the early development of coin production,” write the scientists. That said, the provenance of the Guanzhuang foundry has not been determined, but as the researchers point out, it does seem that the “minting activities were at least acknowledged by the local government.”

The discovery also reminds us that currency is technology, and as such, it is steadily evolving. Today, minting has taken on a new form, as miners of various cryptocurrencies use their resource-hungry server farms to generate wealth. Kind of makes you wonder what currency might look like hundreds of years from now, but whatever it is, it could make crypto look as archaic as spade coins.

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