Originally Posted By: TheFallibleFiend

p. 63, "At times soldiers were even paid in salt, which was the origin of the word salary and the expression 'worth his salt.' In fact, the latin word sal became the French word solde, meaning pay, which is the origin of the word, soldier."

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According to etymology online salarius refered, not to being paid in salt but to being paid an allowance for the purchase of salt.