The use of salt is thought to have begun around 5,000 years ago. And that it became established in countries such as Babylon, Egypt, China and pre-Columbian civilizations.

In primitive European societies, it was extracted during the Bronze Age. Its use was reserved for coastal populations. Reserves were subject to periods of scarcity, determined by unfavorable weather conditions and periods of rising sea levels, making access difficult.

Visit salt was considered a rare and precious commodity, sold by the weight of gold. On several occasions, it was used as currency for purchases and sales. Among the oldest historical examples. The best-known is the Roman custom of paying part of a soldier's pay in salt. This is the origin of the word "salary".

During the reign of D. João I (14th century), so much salt was produced that the government facilitated its export abroad. This represented a major economic advantage. Among the countries that consumed the most Portuguese salt were Holland, Denmark, Norway, France, Sweden and the UK.

Portuguese salt has always been considered to be of the highest quality. Both in Portugal and abroad, it was therefore also a privileged product exempt from all taxes and tolls.

Aveiro salt

Records show that Aveiro's salt began to be mined in the Middle Ages. The evaporation process was still in use in 2022.

The start of salt mining coincided with the formation of the lagoon itself. Anthropogenic factors were fundamental to salt production in the region.

However, to this natural factor must be added others of an anthropic nature. These are manifesting themselves in a socio-political context that is absolutely crucial for salt production in the area of the future Aveiro lagoon.

With the final capture of Coimbra from the Moors in 1064. The battlefield shifted inexorably southwards. North of the Mondego river, the territory was pacified and had become definitively Christian. It offered the security and stability needed to consolidate people and settlements, and to explore all the resources nature had to offer.

The intense salt trade meant that the city gates on the seaward side had to be left open at night, to allow ships to be loaded and, above all, to ensure that they were not interrupted.

Early 16th century. The Ria canal, which was still being formed, was deep enough to allow access for ships and caravels, and the first shipping campaigns began. cod fishing to Newfoundland. The town was prosperous, with many foreigners making a living from the salt industry.

By the end of the 16th century, however, the bar was in a poor state of repair. Caused by its continuous southward movement and the silting up of the sands, due to the stormy winter of 1575. Reflected in trade and the outbreak of epidemics, which led to the depopulation of Aveiro and surrounding villages.

The town was in a sad state, impoverished, with a high mortality rate and a low birth rate. In 1759, despite the terrible conditions, the town was elevated to the rank of city by the Marquis of Pombal.

The atrophy and silting up of certain canals led to a reduction in salinity levels in sections of the Ria no longer suitable for salt production. Aveiro's salt monoculture lost its appeal from the 1870s onwards, allowing the development of other economic activities, namely fishing and also the traditional harvesting of seaweed in the Ria.

Between 1860 and 1870, there were 270 active saltworks in Aveiro. By 1994, the number had fallen to 49. Today, only 9 salt marshes remain active.