Origins of saltern exploitation:

From our current perspective, it's almost unconceivable that something so abundant and low cost would had had such an historical importance. However it has to be taken into account/noted that salt was, and is, essential in a lot of industrial processes and in human and animal diet. It was even more important before the development of industrial cooling, since it was one of the most effective methods of preserving food. As a matter of fact, salt was the cause of war and forced peace, of death and crownings, of richness and poorness, the creation and destruction of towns and cities, and of course, greed. But also happiness of the human being. To demonstrate this, we only need to make a small tour through the history of Añana...

The first traces of settlements near salt springs date back to 5,000 years ago. Since then their inhabitants adapted to interests and peculiarities of each era. In the Iron Age, they left the bottom of the slopes and built their houses on easily defendable elevated sites. Already in Roman times, the settlement system suffered a big change. Probably due to the importance of the salt of Añana, just a few kilometers from the mine, below the present town of Espejo, emerged a city called Salionca by the famous geographer Ptolemy. Its economic development attracted to the surrounding population, who left their places of residence in the old forts to go live on the thriving city.

Around the fifth century, Salionca was destroyed after suffering a major fire. We don't know if this even is related to the barbarian invasions that ravaged the zone. What the archeologists have been able to document is that the city was abandones and part of its inhabitans went to live and work to the salt valley.