Scholar Charles Howard McIlwain wrote that the General Court of Catalonia had a better defined organization than the parliaments of England or France.

[2] Unlike the Courts of Castile, which at the time functioned mainly as an advisory body to which the king granted privileges and exemptions, the Catalan Courts was a regulatory body, as their decisions had the force of law, in the sense that the king could not unilaterally revoke them, being the first parliament of Europe that officially obtained the power to pass legislation, alongside the monarch.

[4] The ecclesiastical arm was presided by the Archbishop of Tarragona and comprised the Catalan bishops, the prior of Catalonia of the Knights Hospitaller, the castellan of Amposta, the abbots with possession of the abbey, the priors of convents with chapter, without superior in the Principality and with mer and mixed imperium over their vassals, the commanders of the Knights Hospitaller (in principle) and the chapters of the cathedrals.

The Duke of Cardona was the president of the military arm, the other titular noblemen (marquises, counts and viscounts) as well as knights and other minor nobles were summoted to the Courts.

The Courts were summoned and presided by the king as count of Barcelona[5] who opened with a royal proclamation while the estates were in charge of legislating, always with the support of the sovereign.

The financial and military power of the counts of Barcelona was quite limited due to the impact of the Feudal revolution during the regency of countess Ermesinde of Carcassonne (1018–1044).

[8] (from Catalan: "We want, we statue and we order: if we and our successors want to make any general constitution or statute in Catalonia, we will submit them to the approval and consent of the prelates, of the barons, of the knights and of the citizens or, from those apellates, of the largest and healthiest part of those.").

In the Parliament of 1358–1359, held in Barcelona, Vilafranca del Penedès and Cervera under King Peter IV, Castile invaded the kingdoms of Aragon and Valencia.

This circumstance prompted the Courts to appoint twelve deputies with executive powers in taxation and some oïdors de comptes ("auditors of accounts") who controlled the administration, constituting the Deputation of the General (Catalan: Diputació del General), later often known as "Generalitat", under the authority of Berenguer de Cruïlles, bishop of Girona, who is regarded as the first President of the Generalitat.

[10] In these Courts, the first ones of Ferdinand II the Catholic, many issues that remained pending after the Catalan Civil War (1462–1472) were resolved: the role of the Deputation of the General, the pactism and the return of properties.

In order to solve the lack of representation and get advice of the troubles of the Principality, the Generalitat frequently summoned the Junta de Braços (States-General), a non legislative assembly composed by members of the Catalan Courts which were in Barcelona at that time.

In the Courts of 1626 the king tried to pass the proposal of Union of Arms designed by his chief minister Gaspar de Guzmán, Count-Duke of Olivares, demanding a military contribution from every realm of the Spanish Crown, including the Principality of Catalonia.

The last General Court of Catalonia, presided by the disputed Habsburg king Charles III were held in Barcelona in 1705–1706, which, according to historian Joaquim Albareda, represented an important advance in the guarantee of individual, civil and political rights (among them, the establishment of the secrecy of correspondence),[13] while at the same time they consolidated most of the constitutional reforms of the last previous Courts (1701–1702) such as the Court of Contraventions (Catalan: Tribunal de Contrafaccions), created in order to ensure the application of the constitutions and solve and prosecute any act (included the ones done by the king or his officers) contrary to the Catalan legislation.