About 4,700 years ago, the Chinese Png-tzao-kan-mu, one of the earliest known writings, recorded more than 40 types of salt. It described two methods of extracting and processing salt, similar to methods still in use today.
Writings on salt no doubt also existed on the clay tablets of Ancient Babylon and on Egyptian papyri. Even without written evidence we can be fairly certain that salt-making and use was a feature of life in all ancient communities. Where isolated from modern trade and technology, some still today make salt by the same prehistoric methods.
In the British Isles, prehistoric man will have made his salt from sea water or from the few places where inland brine springs had been discovered. Traces of these activities are difficult to identify but archaeological evidence is now reaching back into the Bronze Age.
Cheshire was on a Neolithic trade route which crossed the salt fields where Iron-Age Britons probably traded Westmoreland stone axe-heads for salt.