The Parliament is currently made up of 135 members, known as deputies (diputats/deputats/diputados), who are elected for four-year terms or after extraordinary dissolution, chosen by universal suffrage in lists of four constituencies, corresponding to the Catalan provinces.
The first representative and legislative bodies in Catalonia were the Comital Court (Catalan: Cort Comtal) of Barcelona, modelling after the Frankish curia regis, and the Peace and Truce of God Assemblies (Assemblees de Pau i Treva), of which the earliest record dates from 1027.
The last ones were originally ad hoc, local meetings convened by the clergy (Oliba, Bishop of Vic, who died in 1046, was a notable instigator) but progressively became subsumed into the court of the Counts of Barcelona.
The first Catalan legal code, the Usatges de Barcelona, was promulgated by Count Ramon Berenguer I based on the decisions of these assemblies.
Although the counts of Barcelona, had greatly extended the territory under their control, their financial and military power was quite limited, due to the impact of the Feudal revolution during the regency of countess Ermesinde of Carcassonne (1018-1044).
Although the Catalan Courts met at irregular intervals, it also formally approved the acts of the between the King and their sessions (known as pragmàtiques) and, from 1359, established a permanent delegation to oversee the Crown (the Deputation of the General, forerunner of the Generalitat de Catalunya).
The first achievement of Catalan nationalism (led at that time by the Regionalist League), the Commonwealth of Catalonia (1914–25), was an institution composed by the provincial councils (diputaciones) of Barcelona, Girona, Lleida and Tarragona, which included a general assembly made up by representatives from the four provinces, but lacking legislative powers.
The Parliament appointed the ERC leader, Francesc Macià, as president of the Generalitat and, right after the election, the institution began to pass progressive legislation in different areas, such as health, culture and civil law, however, the institution was suspended between 1934 and 1936 when the Government of Catalonia attempted to create a Catalan State within a Spanish Federal Republic after, among other reasons, the rightward turn of the Republican government by its inclusion of CEDA ministers, self-proclaimed anti-Marxist and anti-democratic totalitarian traditionalists close to the European fascists, and the rejection by the Republican Court of Constitutional Guarantees (Constitutional Court of that time) of the emancipatory Crop Contracts Law land reform bill passed by the Parliament of Catalonia.
[6] After the death of Franco in 1975 and the subsequent first years of Spanish transition to democracy, claims by most of Catalan society and political spectrum, from communists to liberals, to restore self-government grew.
Since 1980, the 135 members of the Parliament of Catalonia are elected using the D'Hondt method and a closed list proportional representation, with a threshold of 3% of valid votes—which includes blank ballots—being applied in each constituency.
The building was designed by the Flemish architect Jorge Próspero de Verboom between 1716 and 1748 to serve as an arsenal, in the fortress of the Citadel that King Philip V had built, shortly after having conquered the city of Barcelona, on 11 September 1714.
[12] After the destruction of the Citadel, in 1868, the old arsenal was converted into a palace by the architect Pere Falqués, in order to receive the royal family during the 1888 Barcelona Universal Exposition.
The building was renovated by the decorator Santiago Marco, transforming the throne room into the session chamber, and on the facade the Bourbon coat of arms was replaced by the Blazon of Catalonia.