If there is one thing I would like my kids to learn from me, it is that one of the greatest, most impactful human inventions of all time is the double-entry bookkeeping system for accounting. If my son or daughter ever throws that term out in class when a teacher is writing a list of inventions on the board, there may be some “ums” and blank stares in the classroom, but I would be very proud.

Tim Harford reminds us of how important the double-entry system is, and of the system’s historical origin, in his essay “The Tyranny of Spreadsheets”:

In the late 1300s, the need for a solid system for accounts was evident in the outbursts of one man in particular, an Italian textile merchant named Francesco di Marco Datini. Poor Datini was surrounded by fools.

“You cannot see a crow in a bowlful of milk!” he berated one associate. “You could lose your way from your nose to your mouth!” he chided another.

Iris Origo’s vivid book The Merchant of Prato describes Datini’s everyday life and explains his problem: keeping track of everything in a complicated world.

Some of us have always needed to keep track of everything. The knock-on effect of accountancy, going back to antiquity, is that someone wrote down what people owned and traded, what was abundant and what was rare, and even what came from where. Because of that, we have been able to learn the languages and numeric systems people wrote with, and what people valued, how they traded, and much more, in cultures that have long since passed away. It isn’t all because of the double-entry system in particular, but I think it is pretty interesting nonetheless.