Picture a merchant from the ancient city of Mohenjo-daro, roughly 4,000 years ago, packing for a long trip. He wraps up his goods, kisses his family goodbye, and slips a small, beautifully carved square of soapstone into a pouch around his neck. That little object—smaller than a postage stamp—is arguably his most valuable possession. Without it, he's a nobody. With it, he can prove who he is, unlock credit hundreds of miles from home, and vouch for the quality of his goods.

Archaeologists have unearthed thousands of these tiny carved seals across the Indus Valley, from the mountains of Afghanistan all the way to Mesopotamia. And the more we study them, the more they resemble something startlingly familiar: the humble business card, only with superpowers.

Imagine trying to prove you're really you in a world without passports, driving licenses, or even paper. This was the daily reality for anyone doing business in the Indus Valley Civilization, which stretched across roughly 1.25 million square kilometres at its peak. Their solution was elegant: a tiny carved seal, usually made from steatite (soapstone), featuring a unique combination of imagery and symbols.

Most seals depict an animal—a humped bull, a unicorn-like creature, an elephant, or a rhinoceros—paired with a short inscription in the still-undeciphered Indus script. What's remarkable is how varied they are. Archaeologists have catalogued thousands, and the specific combinations of motifs, script arrangements, and stylistic quirks appear to be genuinely individual. It's a bit like how no two signatures look quite the same, except carved in stone and considerably harder to forge.

When our merchant arrived in a distant port like Dilmun (modern Bahrain), he could press his seal into wet clay and, essentially, sign for himself. Trading partners who had never met him personally could match his seal impression against records or letters of introduction. The seal was him, in miniature.

Takeaway

Identity has always been a technology problem. Long before biometrics and blockchain, humans were solving the same puzzle with clay and a bit of carved stone.

Here's where things get genuinely clever. Archaeologists have found lumps of hardened clay—called sealings or bullae—covered in seal impressions, often with fingerprints and traces of the string or fabric they once bound. These little clay tags were the ancient equivalent of a receipt, an invoice, and a credit reference all rolled into one gritty package.

When a merchant shipped goods, he'd tie the bundle shut, press wet clay over the knot, and stamp it with his seal. If the seal was broken on arrival, someone had tampered with the shipment. But there's more: the seal impression also told the receiver who vouched for the goods. Over time, certain seals gained reputations. A seal from a well-known merchant meant quality, reliability, and—crucially—creditworthiness.

Sites like Lothal, an ancient port city, have yielded warehouses filled with these sealed bundles. Some show impressions from multiple seals, suggesting complex transactions where goods passed through several hands, each vouching for the next. It's not quite Visa, but the underlying idea—reputation as currency—was already ancient by the time our merchant tied his knots.

Takeaway

Trust is the original credit system. Every payment we make today rests on a chain of reputations that stretches back to a clay tag pressed by a merchant we'll never meet.

Not every seal was purely personal. Look closely at large collections and patterns emerge—certain motifs cluster together, certain symbols repeat across seals found in specific workshops or neighbourhoods. Many archaeologists now believe these represent something like guild membership: visual shorthand indicating you were a certified potter, a licensed metalworker, or a member of the merchant class authorized to trade certain goods.

Consider the famous "unicorn" seals, which make up around 60% of all Indus seals discovered. The consistency of the design suggests it wasn't just decorative—it likely marked a specific class of trader or official. Meanwhile, seals showing seated figures in what looks like ritual posture may have belonged to priests or religious functionaries. Different motifs, different professional worlds.

This matters because it hints at a sophisticated society where roles were formalized, skills were certified, and reputation extended beyond the individual to the group. When you saw a certain seal, you knew not just who you were dealing with, but what they were qualified to do. Rather like spotting the letters after someone's name today, except considerably more decorative and involving fewer awkward LinkedIn requests.

Takeaway

Credentials aren't a modern invention—they're a permanent feature of complex societies. Wherever humans specialize, they invent ways to signal expertise.

Next time you fish a business card out of your wallet or tap a contactless payment, spare a thought for our Indus merchant, thumbing his soapstone seal for luck. The technology has changed dramatically—the human need behind it hasn't shifted much at all.

We still need to prove who we are, vouch for our reliability, and signal what we're good at. The Indus Valley figured this out with animals, symbols, and clay. We just do it with slightly shinier materials and rather more paperwork.