In June 1978, Castile and León obtained the pre-autonomy, through the creation of General council of Castile and León by Royal Decree-Law 20/1978, of June 13.

In times of the First Spanish Republic (1873-1874), the federal republicans conceived the project to create an federated state of eleven provinces in the valley of the Spanish Douro, that would also have included the provinces of Santander and Logroño. Very few years before, in 1869, as part of a manifesto, federal republicans representatives of the 17 provinces of Albacete, Ávila, Burgos, Ciudad Real, Cuenca, Guadalajara, León, Logroño, Madrid, Palencia, Salamanca, Santander, Segovia, Soria, Toledo, Valladolid and Zamora proposed in the so-called Castilian Federal Pact the conformation of an entity formed by two different “states”: the state of Old Castile -that is presently built for the current Castilian-Leonese provinces and the provinces of Logroño and Santander-, and the state of New Castile -which conforms to the current provinces of Castile-La Mancha plus the province of Madrid-. The end of the Republic, at the beginning of 1874, thwarted the initiative.

In 1921, on the occasion of the fourth centenary of the Battle of Villalar, the Santander City Council advocated the creation of a Castilian and Leonese Commonwealth of eleven provinces, idea that would be maintained in later years. At the end of 1931 and beginning of 1932, from León, Eugenio Merino elaborated a text in which the base of a Castilian-Leonese regionalism was put. The text was published in the Diario de León newspaper.

During the Second Spanish Republic, especially in 1936, there was a great regionalist activity favorable to a region of eleven provinces, and even bases for the Statute of Autonomy were elaborated. The Diario de León advocated for the formalization of this initiative and the constitution of an autonomous region with these words:

Join in a personality León and Old Castile around the great basin of the Douro, without to fall now into provincial rivalries.

— Diario de León, May 22, 1936.

The end of the Spanish Civil War and the beginning of Franco regime ended the aspirations of the autonomy for the region. The philosopher José Ortega y Gasset collected this scheme in his publications.

After the death of Francisco Franco, regionalist, autonomist and nationalist organizations (Castilian-Leonese regionalism and Castilian nationalism) as Regional Alliance of Castile and León (1975), Regional Institute of Castile and León (1976) or the Autonomous Nationalist Party of Castile and León (1977). Later after the extinction of these formations arose in 1993 Regionalist Unity of Castile and León.

At the same time, others of Leonesist character arose, such as the Leonese Autonomous Group (1978) or Regionalist Party of the Leonese Country (1980), which advocated the creation of a Leonese autonomous community, composed of provinces of León, Salamanca and Zamora. The popular and political support that maintained the uniprovincial autonomy in León became very important in that city.