Short answers, pulled from the story.
The Crown of Aragon originated in 1137 through the dynastic union of the Kingdom of Aragon and the County of Barcelona, arranged by the betrothal of Petronilla of Aragon to Raymond Berenguer IV of Barcelona. Their son Alfonso II, who ascended the throne in 1162, was the first ruler in whom both titles were combined.
At its height in the 14th and 15th centuries, the Crown of Aragon controlled much of eastern Iberia, parts of southern France, the Balearic Islands, Sicily, Corsica, Sardinia, Malta, Southern Italy from 1442, and parts of Greece until 1388. Its territories now fall within modern Spain, France, Italy, Greece, Malta, and Andorra.
The Crown of Aragon was a composite monarchy where the king ruled each constituent state separately under its own laws, parliaments, and tax structures. Aragon, Catalonia, and Valencia each maintained their own legislative bodies called the Cortes or Corts, and each had a Diputacio del General or Generalidad. The historian Juan de Contreras y Lopez de Ayala described it as more like a confederacy than a centralised kingdom.
Sicily came to the Crown of Aragon after the Sicilian Vespers of 1282, when the island's population rose against the Angevin dynasty and massacred garrison soldiers. Peter III of Aragon responded to their appeal and landed at Trapani five months later. Pope Martin IV retaliated by excommunicating Peter and offering the Kingdom of Aragon to a son of Philip III of France.
The Crown of Aragon was abolished between 1707 and 1716 by the Nueva Planta decrees issued by Philip V of Spain following the defeat of Archduke Charles in the War of the Spanish Succession (1701-1714). The decrees dissolved its institutions, imposed Castilian as the language of government, and merged its territories into a centralised Kingdom of Spain.
The Llibre del Consolat del Mar, written in Catalan, is one of the oldest compilations of maritime law in the world. It documented the thalassocratic authority of the Crown of Aragon, which exercised broad rule-setting power across the Mediterranean Sea.