A controversial natural border: The making of the Spanish-Portuguese boundary along the Minho River (1855-1866)

Within this framework, the paper initially addresses main practices and discourses about territory in this particular Iberian context, regarding both the enduring relevance of theory of natural boundaries within European history of modern state-making and legal codification of river boundaries delimitation by Spanish and Portuguese law internationalists. The following part of the paper presents main historical problems and territorial border disputes along the Minho River which the 1864 Spanish-Portuguese Boundary Treaty attempted to settle. Discussions and negotiations taking place within the Joint Boundary Commissions in charge of examining, delimiting and demarcating this stretch of the border are analysed as to consider how diverging interest and competing discourses about this fluvial space were displayed and related eventually to the solutions adopted by the Boundary Treaty. In that sense, state-driven boundary-making proved to be an important tool for territorial management of this border space.