text: Portuguese, Norman, Breton, and English fisherman were the first to adopt the salt-based curing technique from Basque fishermen in Newfoundland near the cod-rich Grand Banks by the late 1500s. By the 1700s, salted cod had become a staple food for ordinary Portuguese people and by upper levels of Portuguese society. With the advancements in freezing and transportation in the 1900s, salted cod from North America declined and Iceland and Norway became the major supplier of the salted fish to Portuguese markets. During this time  was a cheap source of protein and frequently consumed. Thus,  became a staple of the Portuguese cuisine, nicknamed  ('loyal friend'). In fact, in Portugal, cod always refers to salted, dried codfish and it is very rare to find fresh cod () for sale.
  This dish is also popular in Portugal and other Roman Catholic countries because of historical fasting rules, which forbade the eating of meat on many days (Fridays, Lent, and other festivals), and so  dishes were eaten instead.   is also popular in Sfax where this dish is eaten with chermoula on the first day of Eid ul-Fitr .
  In Portugal,  is often sold as a generic product with no brand information. Customers are free to touch, smell, and otherwise personally inspect the fish, which is very different from how fresh seafood is often sold. Stores can carry a large variety of  differing in color, size, smell, taste, and dryness. Such variation has led Portugal to define requirements as to what products can carry the label . They are however, graded by weight which often defines what price category the  is sold under. The largest is , which are large pieces of whole fish weighing more than 4kg. Following this are  (4-2kg),  (2-1kg),  (1-0.5kg) and  (below 500g).