The Army of Catalonia that initially fought in support of the Habsburg dynasty's claim to the Spanish throne were finally defeated at the Siege of Barcelona by the army of the Bourbon king Philip V of Spain on 11 September 1714 after 14 months of siege. That meant the loss of the Catalan constitutions and the institutional system of the Principality of Catalonia under the aegis of the Nueva Planta decrees, and the establishment of absolutism.
The holiday was first celebrated on 11 September 1886. In 1888, coinciding with the inauguration of the Barcelona Universal Exposition, a statue in honor of Rafael Casanova was set up, which would become the point of reference of the events of the Diada. The celebration gained popularity over the following years; the Diada of 1923 was a great mass event, with more than a thousand floral offerings, acts throughout Catalonia and a certain institutional participation. But the demonstrations caused 17 wounded, five policemen and 12 protesters, and several arrests. The dictatorship of Primo de Rivera banned the celebration. During the Second Spanish Republic (1931–1939), the Generalitat de Catalunya (the autonomous government of Catalonia) institutionalized the celebration.
It was suppressed by Francoist Spain in 1939, and relegated to the family and private sphere, but continued to be celebrated clandestinely. The monument of Rafael Casanova was removed. Since 1940 the National Front of Catalonia took advantage of the day to carry out some propaganda actions: distribution of anti-fascist leaflets, clandestine hanging of senyeres, etc. It was celebrated publicly for the first time again on 11 September 1976, followed by
a huge demonstration demanding Catalan autonomy in Barcelona the next year, on 11 September 1977, in which the Casanova's statue was repositioned in its place, and the celebration was reinstated officially in 1980 by the Generalitat de Catalunya, upon its restoration after the Francoist State, becoming the first law approved by the restored Parliament of Catalonia.