The municipality of Barcelona is the result of the annexation in the late 19th and early 20th century of the different municipalities that were formerly in the plain of Barcelona.
The Nueva Planta decrees of the 18th century eliminated the autochthonous governing bodies of the territory of Barcelona, based on the representation of the different citizen branches in the Consejo de Ciento (Council of One Hundred), and they were replaced by absolutist bodies of royal designation. With the Cadiz Constitution of 1812, the city councils were created as bodies of popular representation and, with them, the municipalities.
At that time the city of Barcelona was what is now called Ciutat Vella. Its boundaries also included Montjuic, the Pueblo Seco, and most of the territory of the later Ensanche, but these were practically undeveloped lands. In 1839 an exchange with the municipality of Santa Maria de Sants incorporated the land near the Creu Coberta (today's neighborhoods of Hostafrancs and La Font de la Guatlla) to Barcelona in exchange for some land in La Marina de Port.[1]
Throughout the 19th and 20th centuries, Barcelona annexed the rest of the municipalities of the surrounding plain. With substantial differences, the configuration of these former municipalities served to design the ten districts into which the city is currently divided.