Ramiro I was the first King of Aragon from 1035 until his death, although he is sometimes described as a petty king. He would expand the nascent Kingdom of Aragon through his acquisition of territories, such as Sobrarbe and Ribagorza, and the city of Sangüesa. Sancho Ramírez, his son and successor, was King of Aragon, but also became King of Pamplona.

The Kingdom of Aragon was a medieval and early modern kingdom on the Iberian Peninsula, corresponding to the modern-day autonomous community of Aragon, in Spain. It should not be confused with the larger Crown of Aragon, which also included other territories—the Principality of Catalonia, the Kingdom of Valencia, the Kingdom of Majorca, and other possessions that are now part of France, Italy, and Greece—that were also under the rule of the King of Aragon, but were administered separately from the Kingdom of Aragon.