Among the most successful and long-lived portals in business history were the great fairs held in the Champagne region of France in the 12th and 13th centuries. For about 200 years they were the places to do business in Europe. All the Continents good, the silks and oils of the south, the furs and grains of the north, came here to be sold and bought. These were wholesale markets, not retail, but they were the Comdex of mediaeval business-to-business commerce; everyone who was anyone had to come.

The fairs, there were six, lasted two months each, and the secret of their commercial dominance was what happened in the second month, when the selling of goods died down and was replaced by a settling of accounts. According to Fernand Braudel, the great historian of early capitalism, "The originality of the Champagne fairs lay less in the superabundance of goods on sale than in the money market and the precocious workings of credit on display there. Financiers and bankers, mostly Italian, set up tables and exchanged currencies, bought and sold short-term credit instruments, even did a little arbitrage. Double-entry bookkeeping hadn't been invented yet, but just about every financial instrument known today (except those that bring down hedge funds) had been.

The fairs eventually declined, partly because new land and sea trading routes opened up, but their central role in finance persisted long after they ceased to be the centre of trade in goods. That suggests, Braudel says, that the fairs became portals not because they aggregated stuff but because they provided an efficient mechanism for performing transactions and obtaining financial leverage.