The term is conventionally credited to Emilio Mola Vidal, a Nationalist general during the Spanish Civil War (1936–39). As four of his army columns moved on Madrid, the general referred to his militant supporters within the capital as his “fifth column,” intent on undermining the loyalist government from within.

Why are they called the fifth column?

Fifth column, a translation of the Spanish quinta columna, was inspired by a boast by rebel general Emilio Mola during the Spanish Civil War. Mola predicted Madrid would fall as four columns of rebel troops approaching the city were joined by another hidden column of sympathizers within it.

What are the 4 columns?

The Four Columns ("Les Quatre Columnes" in Catalan) are four Ionic columns originally created by Josep Puig i Cadafalch in Barcelona, Spain. They were erected in 1919, where the Magic Fountain of Montjuïc now stands.