From the first days of the Peninsular War, which erupted in Spain in resistance to the French invasion and occupation of the peninsula, local ruling bodies or "juntas" appeared as the underground opposition to the French-imposed government. They were established by army commanders, guerrilla leaders or local civilian groups. Convinced that unity was needed to co-ordinate efforts against the French and to deal with British aid, several provincial juntas, in Murcia, Valencia, Seville and Castile and León, called for the formation of a central body. After a series of negotiations that included the discredited Council of Castile, a Supreme Central Junta met in Aranjuez on 25 September 1808. Serving as surrogate for the absent royal government, it called for representatives from local provinces and overseas territories to meet in an "Extraordinary and General Cortes of the Spanish Nation." It was so called because it would be both the legislative body for the empire and the body that would write a constitution for it. By the beginning of 1810, the forces under the Junta's command had suffered serious military reverses at the battles of Ocaña and Alba de Tormes. The French inflicted large losses on the Spanish, took control of southern Spain and forced the government to retreat to Cádiz, its last available redoubt on Spanish soil.