The club’s all-white home kit means that Real Madrid nicknames such as "Los Blancos" (the Whites) and "Los Merengues" (the Meringues) require little explanation. However, another common nickname, "Los Vikingos" (the Vikings), for the 14-time European Cup winners does need a little bit of unpacking.

It is not uncommon to see Madrid fans wearing the horned helmets traditionally associated with Vikings, who were seafaring raiders, pirates, explorers, and colonizers who traveled from parts of Scandinavia now known as Denmark, Sweden, and Norway and settled in areas across Europe and beyond between the 9th and 11th centuries.

Viking imagery is also frequently seen on the large tifos that Madrid fans are known for unfurling inside the stadium on special occasions. For example, before a Spanish capital derby against Atlético Madrid in 2017, supporters unveiled a banner depicting a Viking sitting on a throne, with broken shields bearing the red and white of Atlético at his feet. The image came with the message, "The throne is ours."

So what is the origin of the nickname "Los Vikingos"?

Its provenance appears to be the subject of two main theories.

One dates back to Real Madrid's famous European Cup victory in 1960, when a team featuring Alfredo di Stéfano and Ferenc Puskas thrashed Eintracht Frankfurt 7-3 to win the club's fifth consecutive continental title, and the nickname is credited to the UK newspaper the Times. Following what is regarded as one of the greatest finals in tournament history, a Times article is widely reported to have compared Madrid's dominance of Europe to that of the Vikings.

The second main theory centers on Real Madrid's transfers in the 1970s, when they signed Henning Jensen, the first-ever Danish player for the team, as well as three highly regarded German players in Günter Netzer, Paul Breitner, and Uli Stielike. The arrival of such players is said to have given rise to the nickname "Los Vikingos," in part because of Germany's proximity to Scandinavia (and Spaniards' slender propensity to refer to any pale-skinned, fair-haired northern European as being "nórdico").

According to the theory, the nickname was created by Atlético fans, who were allegedly inspired by physical characteristics that resemble stereotypical ideas of a Viking's appearance. The German and Danish players had long, voluminous hair, which was fashionable at the time. Although Breitner and Stielike had darker hair than the blond Netzer and Jensen, both tended to have a prominent, bushy moustache or beard.