The purpose of this paper is to analyse some essential events concerning the relationship between Spain and Macao in the middle of the 19th century. Macao remained as a privileged spot for the commercial activities of Spain in China after the opening of the international ports agreed upon in the Treaty of Nanjing in 1842. This encouraged Spanish diplomatic representatives to render special attention to the Portuguese enclave. This became the origin of a shocking proposal for the military conquest of Macao and its surrounding territories by one of these representatives, Sinibaldo de Mas. Although this proposal was never taken under consideration, it helps us to better understand the role Macao played in Spanish strategies in China. Years later, Mas participated as a mediator when the Chinese government attempted to regain sovereignty over Macao by paying an economic compensation to Portugal. The involvement of Sinibaldo de Mas in this project has a strong symbolic meaning, making him a key agent in the relations between Spain and Macao in the 19th century.

El propósito de este trabajo es analizar algunos hechos esenciales relativos a la relación entre España y Macao a mediados del siglo XIX.

El propòsit d'aquest treball és analitzar alguns fets essencials relatius a la relació entre Espanya i Macao a mitjan segle XIX.