Spanish football fans have grown up referring to Barcelona fans as “culés” and Real Madrid fans as “vikingos”. They are expressions that are fully normalized, although the origins of these two nicknames that even reach outside the Spanish borders have rarely been analyzed.
In the case of Barcelona, the birth of this nickname is quite clear. You have to go back to the time when the Blaugrana played their home games at the Les Corts pitch (between 1922 and 1957). The expectation was such every time Barça played, that the stadium did not have enough space to accommodate all the fans. For this reason, it was common for many fans to sit on the walls that surrounded the pitch. From the outside, what passers-by saw were the buttocks of the fans, which is why they began to be known as “culers”, that is, those who show the “cul” (ass). The pronunciation is culés, a name that ended up lasting over time until today.
In the case of vikings, there are two theories. The first dates back to the 60s and it is said that there was an article in The Times in which he said that “Real Madrid walks around Europe like the Vikings used to walk around, destroying everything in its path”.
The other theory goes a little further in time, also coinciding with the time when this nickname began to become popular. In the 1970s, Madrid signed several soccer players from northern Europe (Netzer, Breitner, Stielike or Jensen). They all had a Nordic look reminiscent of the Vikings and it is said that this was when Madridistas began to be known in this way.