April 15th is a date seared into the brains of most Americans—being the due date for us to turn in our tax returns to the Internal Revenue Service. In the modern era, most governments have wide-ranging powers to tax their populaces. Yes, you have problems with tax evasion here and there, but most urban dwellers are used to paying taxes as a matter of course (though we certainly aren’t happy about it).

When you think about it, though, the smooth collection of taxes requires a vast infrastructure of information processing, bureaucracy, and coercive enforcement if necessary. All of that came about very late in historical terms. In the United States, tax withholding from our salaries was only instituted during World War II, for example. (In a delicious bit of historical irony, the concept was developed in part by famed free-market economist Milton Friedman, when he worked for the Treasury in the early days of the war. For the rest of his life, he hoped that tax withholding would eventually be abolished.) The first income tax in the United States was a temporary measure enacted during the Civil War.

In other countries, the story was similar. The seminal work on this subject, at least in comparative politics, is Margaret Levi’s Of Rule and Revenue, a study of taxation systems throughout history. Levi’s basic argument is that rulers are constrained in how they can tax populations by their ability to coerce the people, the ease with which money can be hidden, and limitations in measuring technology. (I previously wrote of similar concerns behind the institution of English nobility.) In short, early rulers had a very hard time raising taxes directly, simply because it was next to impossible to extend their control over the populace.

So what did they do? The strategies of rulers were many, but in this piece I want to focus on a particular practice called “tax farming.” In its basic form, the ruler created some sort of tax or tariff—a 10% tax on salt, for example—but rather than collecting the taxes itself, the ruler would sell off the right to collect the tax to some private party. This was the tax farmer. The tax farmer would pay a large sum up front to the government, and in exchange would gain the right to ruthlessly apply the salt tax to anyone within his jurisdiction and pocket the proceeds.

This is not the same as modern privatized tax collection, where the private party must transmit collected taxes to the government. Here, the tax farmer is the direct beneficiary of tax revenue. In general, tax farming was incredibly lucrative for the farmer, while the state was forced to sell the future revenues at discount prices, simply because it lacked the capacity to collect taxes itself. (Here, we see another example of a principal-agent problem.)

A nice (free!) overview of tax farming in the 18th century can be found here, by the eminent scholar Eugene White. The French monarchy, for one, was heavily dependent on tax farming for revenue. This dependence was a major contributor to the French Revolution, for two reasons. First, royal revenues were always rather stunted because the tax farmers absorbed much of the take, weakening state power. Second, the tax farmers of France were notorious for harshly oppressing the populace in order to squeeze every last sou that they could. (Similar concerns were at play with the Publicans of ancient Rome; a nice overview can be found here.)

This is all very interesting, but why is it worth knowing? In fact, it is surprising just how relevant the principle of tax farming can be, even in modern society. Take casinos, for example. They pay a large sum of money to local and state governments, and in return gain the right to siphon vast amounts of money from willing gamblers. The voluntary nature of the transaction makes it more palatable, of course, but even then the addictive nature of gambling muddles things.

Even more striking is the history of the banking system. That subject is so fascinating that it deserves its own post, but for now, suffice it to say that for decades, many U.S. states raised nearly half of their revenue by selling monopoly banking charters. In return, a particular bank would be given exclusive control of its town, free to earn considerable profits from its residents.

Neither casinos nor early banks are really the same as tax farming, of course. But they are both indirect means of collecting revenue, in which private parties gain outsized profits compared to the government’s take. Other examples can be seen with only a little effort, and the idea of tax farming is a useful lens for viewing much government policy.

Aside from that, this is another opportunity to bang my hobby horse of more realistic fantasy writing. As noted, tax farming was often the cause of massive oppression of the people, and resulting political unrest. I’d bet my last cent that some budding fantasy author could spin a much more interesting story using tax farming as an ingredient, than the typical “Evil Overlord wants to oppress the peasants for the lulz.”

The key thing to remember is that a king turns to tax farming when he needs more money that he can easily extract with his own efforts. It is the hallmark of lands with difficult travel, poor communication, and weak and divided political loyalties. In time, the tax farmers can become extremely powerful in their own right, perhaps even rivaling the established authority in the same way that Italian mercenaries would often overthrow their employers. If that isn’t fertile soil for a good story, I don’t know what is.