Christmas dinner, as well as other festive meals, wouldn't be complete without some Bacalhau—a dried and salted cod fish that originally came from Norway and used to be the food of Vikings.
By the time the Portuguese people brought Bacalhau to Brazil, it was very cheap so that everyone could have it and it became a very popular and important food. This is especially true for slaves and the poor because meat was so expensive.
As a result of overfishing cod for years, the shoals started to deplete, and prices went up. Now Bacalhau has become more exclusive, and it's usually eaten only on holidays or special occasions.