[eyko]

You're correct. Funny enough, this is also obscure knowledge even in e.g Spanish. We use the word salario (from latin salarium) which has the same meaning as in latin: words ending in -ario (lat: -arium) is used to denote association, like in templario (templar) or revolucionario (revolutionary). For some reason, however, nobody thinks of "salario" as something associated with salt (sal). I guess it's so strange in today's world that money would be used for the specific purpose of buying salt, that it simply doesn't click.

[mudita]

This blog by a classicist claims that the word salary is indeed coming from the latin words salarium and sal, but that it is not clear what the connection is, that there is neither evidence for the explanation that Roman soldiers were paid in salt nor that it was an allowance for the specific purpose of buying salt:

http://kiwihellenist.blogspot.com/2017/01/salt-and-salary.ht...

Regarding the latter he writes:

"As I said above, ‘salt allowance’ isn’t a terrible guess. But I strongly suspect it’s much more metaphorical than that. Compare how the Greek word for a salary was opsōnion, literally ‘(money) for buying opson’, where opson means ‘fish, relish, sauce’. That doesn’t mean Greek workers were given a ‘fish allowance’: it means that there was a generalised idea that wages went on traded goods like fish, and not on things like barley which land-owners would grow for themselves. Similarly, in Rome, grain allowances were a common thing; it could easily make sense to interpret salarium as ‘everything-else-money’."

[prox]

In the book on the history of Rome, Livy states : “Again, the monopoly of salt, the price of which was very high, was taken out of the hands of individuals and wholly assumed by the government. Imposts and taxes were removed from the plebs that they might be borne by the well-to-do, who were equal to the burden: the poor paid dues enough if they reared children.”