Is the etymology of "salary" a myth?

Since, perhaps forever, I had always ‘known’ that the English word salary was derived from the Latin salarium, to the time when Roman soldiers were paid in salt for their service. Salt was a highly-prized and sought-after commodity due to its ability to preserve food and was, in part, also responsible for the development of civilization.

However, my world turned upside down when I read the following extract in a blog:

Here’s the simplest form of the myth.

The word ‘salary’ comes from the Latin word for salt because the Roman Legions were sometimes paid in salt.
– Wikipedia, ‘History of salt’

Pure fantasy. There isn’t the tiniest scrap of evidence to suggest this. At all, to any extent, ever.

Peter Gainsford, the academician and author of the blog, Kiwi Hellenist, adds

‘Roman soldiers were paid in salt’ may be the simplest form of the myth, but it’s also a secondary form. […] that seems to indicate that people first started writing about the idea around the 1860s (here, for example).
The older, primary form of the myth is that soldiers were given ‘salt money’, that is, a monetary allowance for buying salt. This, too, is a modern invention.

Wikipedia has since corrected that information, the same historical detail which I had always considered ‘common knowledge’.

The word "salary" comes from the Latin word for salt. The reason for this is unknown; a persistent modern claim that the Roman Legions were sometimes paid in salt is baseless

But Etymonline appears to perpetuate this “myth”

late 13c., "compensation, payment," whether periodical, for regular service or for a specific service; from Anglo-French salarie, Old French salaire "wages, pay, reward," from Latin salarium "salary, stipend, pension," originally "salt-money, soldier's allowance for the purchase of salt," noun use of neuter of adjective salarius "pertaining to salt," from sal (genitive salis) "salt" (from PIE root *sal- "salt").

What is the real history and etymology of salary?

Related but obviously not a duplicate of: I don't know the meaning of "salt allowance"

Solution 1:

There may well be more to this, but to start , John Arbuthnot wrote:

... Tributum, properly speaking, was a Tax upon Individuals; one sort of it was called Capitatio, a Pole-tax (sic). Besides the forementioned Taxes, there were several Excises, as that formerly mentioned laid on by Cato upon Luxury and Expences; which perhaps was only temporary. There was a Salt Tax laid on very early. Ancus Martius made the first Magazines of Salt. Salarium or Salary is derived from Sal. Tables Of Ancient Coins, Weights, And Measures (1754)-

There is no mention of soldiers, only of taxes.

Neither is there a direct reference to soldiers' pay by Pliny the Elder, at least at this point:

All the amenities, in fact, of life, supreme hilarity, and relaxation from toil, can find no word in our language to characterize them better than this. Even in the very honours, too, that are bestowed upon successful warfare, salt plays its part, and from it, our word "salarium" is derived. Pliny the Elder, The Natural History

Pliny seems to be referring to rewards, rather than salary as we now understand it.

Salary arrives in English from Vulgar Latin. It came through French rather than directly from Classical Latin. The word (el salario) also exists in Spanish. It must be thought that the word had been used many centuries to refer to compensation of some sort before being taken into in English. Roman soldiers were certainly issued salt as part of their compensation, otherwise Roman armies could never have made the great marches and fought the grand battles. No doubt Roman soldiers thought of salt as important. But it does not seem "paid in salt" was ever a common practice.

"To be worth one's salt" is an idiom in English that has no certain origin. Possibly Roman soldiers had a similar understanding about salt. As the Roman soldiers were the principle purveyors of Vulgar Latin in the Roman Empire, salt may well have been considered a valuable compensation, valuable enough to give its name to "pay".

Solution 2:

In classical Latin, the word salarium already meant "salary":

salarium proconsulari solitum offerri ... Agricolae non dedit: "the salary commonly offered a proconsul [the governor of a province or, in this case, a high military commander]...he did not give to Agricola" — Tacitus, De vita Iulii Agricolae XLII (written 98 AD)

The (undisputed) conexion to salt had already become merely etymological or historical by that time, for a proconsul was not paid (mainly) in salt nor for the purchase of salt. A military conexion was still apparent. So I think the answer (which I do not have) to this question lies in the pre- or early classical etymology of the word, not in later developments.

You'll probably get a better answer at http://latin.stackexchange.com