The situation surrounding Petronilla’s birth is a strange one. Her father Ramiro was the brother of Alfonso I of Aragon, and he was the bishop of Barbastro-Roda. However, Alfonso died childless in 1134, and he left the crown to the three religious, military orders. However, his wish was not respected, and the aristocracy of Navarre elected a King in the form of his brother. As a bishop, he required a papal dispensation to abdicate from his monastic vows in order to secure the succession to the throne. His marriage to Agnes of Aquitaine (aunt of Eleanor of Aquitaine) was quickly arranged, and she promptly conceived. Petronila, who was to be their only child, was born on 29 June 1136. She was just one year old when she was betrothed to Raymond Berengar IV, Count of Barcelona, who was 24 years old at the time. Later that year her father abdicated in her favour and handed the authority to Raymond Berengar. He returned to monastic life to the Abbey of San Pedro in Huesca. He died there in 1157. Her mother too retired to the monastic life at Fontevraud Abbey. She died around 1159.
In August 1150 the betrothal between Petronilla and Raymond was ratified in a wedding ceremony, and the marriage was consummated in 1151 when she was 15 years old. They would go on to have five children, and she had great trust in her husband. While pregnant with her first child, she bequeathed the Kingdom of Aragon to her husband if she did not survive childbirth.
We do not know how much power Petronilla truly exercised. The absence of both her mother and father must have been painful for her, and we do not know how much contact they had. Her husband died in 1162, and her eldest surviving son was just seven years old when she abdicated in his favour on 18 July 1164. She retired from public life as her father had done before her and died in October 1173, still only 37 years old. She was buried in the Cathedral of Barcelona, but her tomb has been lost.
She certainly made her father’s wish come true. Upon his marriage, he wrote that he ‘took a wife not out of carnal lust, but for the restoration of the blood and the lineage‘ and that lineage lives on until this day.
Stalls, William C. “Queenship and the Royal Patrimony in Twelfth-Century Iberia: The Example of Petronilla of Aragon”, Queens, Regents and Potentates, Women of Power, vol. 1 (Boydell & Brewer, 1995), 49–61. (UK & US)