Ramiro I (bef.1007 - 8 May 1063) is usually credited with being the first King of Aragon. Apparently born before 1007, he was the natural son of Sancho III of Navarre by his mistress Sancha de Aybar. Ramiro was reputed to have been adopted by his father's wife Mayor after he was the only of his father's children to come to her aid when needed, although there is no surviving record of these events, and the story is probably apocryphal.
During his father's reign, he appeared as witness of royal charters starting in 1011, and was given numerous properties in the county of Aragon, and by the division of Sancho's realm on the latter's death in 1035, the county of Aragon fell to Ramiro with the title of baiulus or steward. The foundation traditions of the Kingdom of Aragon would make him the first king, (he is, on account of the small size of his Pyrenean kingdom with its capital at Jaca, sometimes called a "petty king") and he was called king by his vassals, neighbors, the church and even his sons, yet he referred to himself always as simply Ranimiro Sancioni regis filio (Ramiro, son of King Sancho). Likewise, in his wills, he refers to his lands as simply having been given him in stewardship by his half-brother García and by God. He is likewise called regulus (rather than rex used for García) and quasi pro rege (acting as if king) in charters from Navarre.
Ramiro sought to enlarge his lands at the expense of both the Moors and his brother, García. Shortly after the death of his father (the date variously placed from 1036 to 1043), he supported the emir of Tudela in an invasion of the Kingdom of Navarre of his brother García. He was defeated in the Battle of Tafalla, but out of the conflict gained lands, including Sanguesa, and established a state of semi-autonomy. In 1043, apparently with the approval of García, he annexed Sobrarbe and Ribagorza, previously held by his youngest legitimate half-brother, Gonzalo.
Before he was married, Ramiro had a mistress named Amuña with whom he had a natural son, Sancho Ramírez, in whom he confided the government of the county of Ribagorza.
Ramiro's second wife was Agnes (Inés), a daughter of the Duke of Aquitaine. Ramiro set the advance from Aragon toward Huesca and Zaragossa, after annexation of Ribagorza and Sobrarbe. The first charter for the royal town of Jaca is attributed to him, that will set the example of an ideal community (included well defined laws of protection even to non residents) for later urban rights until late in the Middle Ages.
Ramiro died at the Battle of Graus in 1063 while trying to take the city.