Barcelona is a city on the northeastern coast of Spain. It is the capital and largest city of the autonomous community of Catalonia, as well as the second-most populous municipality of Spain. With a population of 1.6 million within city limits, its urban area extends to numerous neighbouring municipalities within the province of Barcelona and is home to around 4.8 million people, making it the fifth most populous urban area in the European Union after Paris, the Ruhr area, Madrid and Milan. It is one of the largest metropolises on the Mediterranean Sea, located on the coast between the mouths of the rivers Llobregat and Besòs, bounded to the west by the Serra de Collserola mountain range.

The Crown of Aragon was a composite monarchy ruled by one king, originated by the dynastic union of the Kingdom of Aragon and the County of Barcelona and ended as a consequence of the War of the Spanish Succession. At the height of its power in the 14th and 15th centuries, the Crown of Aragon was a thalassocracy controlling a large portion of present-day eastern Spain, parts of what is now southern France, and a Mediterranean empire which included the Balearic Islands, Sicily, Corsica, Sardinia, Malta, Southern Italy and parts of Greece.