In 1441, two teams of surveyors drew the same border and made the same mistake. Between their two lines lay a strip of Italy about two miles long that suddenly belonged to nobody. The people living on it noticed.

It began with a debt. Pope Eugene the Fourth owed money to the Medici bank of Florence, and settled it the way popes then could: he handed over a town. The new border between papal land and Florence was defined by a little stream called the Rio. The problem was that there were two streams called the Rio, running parallel, five hundred metres apart. The Pope's surveyors measured to one. The Florentine surveyors measured to the other. The two teams never met to compare notes. And on the hillside between the two lines sat the hamlet of Cospaia: a church, a huddle of farmhouses, and a few hundred farmers who woke up one morning inside a hole in the map. Neither state claimed them. Neither state taxed them. So the farmers of Cospaia declared themselves a free republic.

It should have lasted a month. It lasted three hundred and eighty five years. Cospaia had no taxes, no army, no police, no courts, no prison, and no written laws at all. It was governed, loosely, by the heads of its families meeting in the church, under a motto that said everything: perpetual and firm liberty. And when tobacco arrived in Italy, the little republic found its destiny. While the states around it taxed and restricted the new leaf, Cospaia had no law to restrict anything. Every field filled with tobacco. For centuries, duty free contraband flowed quietly out of the two mile republic into two enormous, heavily taxed, permanently irritated neighbours.

By 1826, the neighbours had finally had enough. The Papal States and Tuscany signed a treaty and divided the strip between them. The fourteen remaining heads of Cospaia's families signed away three hundred and eighty five years of liberty, and the price of a republic turned out to be exactly this: one silver coin per family, and permission to keep growing half a million tobacco plants a year. The hamlet is still there, on its hillside in Umbria, and it still remembers what it was. For nearly four centuries, the freest place in Europe was a clerical error.

Dead serious. I do one of these every day. Subscribe.