Between the eighth century and the first half of the tenth, the ancient community of Valle Salado changed and a network of independent villages appeared. The origins of this significant change in the organizational model of the ancient landscape of Salinas were not based on a single cause, but on a combination of various factors.

As an example, during this period, the area became increasingly unstable due to successive confrontations between the Basques, the Visigoths and the Franks and to the Muslim invasion, which led to pressure being exerted on this area by the emirs, who organised a score of raids between 767 and 886 to loot and destroy the area. Noted among them is the raid that took place in 865 when Emir Abd-al-Rahman ibn Muhammad sent his troops north to raid the castles of Earl Rodrigo and Salinas de Añana, which is mentioned in the text as Al-Mallaha.

This instability led to the development of important feudal powers, both within the community and in the territory. This eventually led, among other factors, to the great community that exploited the salt works to become divided into a network of six completely independent villages that shared Valle Salado with the most important monasteries of the time.

Surviving texts from the tenth century show that at least six villages were established in the valley: Fontes, Terrazos, Villacones, Villanueva, Olisares and Orbón. The residents from the six villages in Valle Salado joined forces with a view to counteracting the growing pressure of the feudal powers and the systemic crises; this also enabled them to preserve the ownership of the salt-pans and brine from the springs, improve the production system and, thus, the productivity and marketing of the salt.

Communal cooperation was advantageous in several steps of the production process, such as in the construction of the terraces and channels, in their maintenance and, above all, in the "entroje", which is the manual transport of the salt from the on-site storage areas to external warehouses, near the workers' homes.

Document from the monastery of San Román de Tobillas (Álava) dated in 822 mentioning the Añana salt works for the first time: "XXXIII salt-pans in Salinas with their well and rations from the springs" (AHN, Clero Secular Regular,Car,N 1r).