Comment by vintermann

One thing that has stuck me in old tax records is that when taxes were paid in natura according to fixed exchange rates (e.g. one cow is two sheep, one measure of butter is three squirrel skins etc.), then government probably actually valued some income more than others. The "market value" of these goods almost certainly didn't match the fixed exchange rates, but people's ability to trade for the best tax unit were also limited (and often legally restricted to the same exchange rates!).

So e.g. pastoralists who paid their tax in actual skins may have been more valued than people who paid their tax in "a skins worth" of grain.

I wonder if there's some good books on this sort of thing.