As the eldest child and heiress presumptive of Alfonso VIII of Castile, she was a sought-after bride, and was engaged to Conrad, the son of Holy Roman Emperor Frederick I.

When her father died, Berengaria served as regent for her younger brother Henry I in Castile until she succeeded him on his untimely death.

Berengaria's claim to the throne was based in part on documentation in the treaty and marriage contract,[12][13] which specified that she would inherit the kingdom after her father or any childless brothers who might come along.

[17] By 1191, Berengaria requested an annulment of the engagement from the pope, influenced, no doubt, by third parties such as her grandmother Duchess Eleanor of Aquitaine, who was not interested in having a Hohenstaufen as a neighbor to her French fiefdoms.

[19] As part of the marriage, and in accordance with Spanish customs of the time, she received direct control over a number of castles and lands within León.

[20] Starting in 1198, Pope Innocent III objected to the marriage on the grounds of consanguinity and even threatened to excommunicate Alfonso, though the couple stayed together until 1204.

[citation needed] Though she had left her role as queen of León, she retained authority over and taxing rights in many of the lands she had received there, including Salamanca and Castroverde,[25] which she gave to her son Ferdinand in 1206.

[31] In 1214, on the death of her father, Alfonso VIII, the Castilian crown passed to his only surviving son, Berengaria's 10-year-old brother, Henry I.

[34] At the end of May the situation in Castile had grown perilous for Berengaria, so she decided to take refuge in the castle of Autillo de Campos, which was held by Gonzalo Rodríguez Girón (one of her allies) and sent her son Ferdinand to the court of his father.

[34] Circumstances changed suddenly when Henry died on 6 June 1217 after receiving a head wound from a tile which came loose while he was playing with other children at the palace of the bishop of Palencia.

[35] His guardian, Count Álvaro Núñez de Lara, tried to hide the fact, taking the king's body to the castle of Tariego, although it was inevitable that the news would reach Berengaria.

[37] Although she did not reign for long, Berengaria continued to be her son's closest advisor, intervening in state policy, albeit in an indirect manner.

[38] One example was how she arranged the marriage of her son with princess Elisabeth of Hohenstaufen (known as Beatriz in Castile), daughter of Duke Philip of Swabia and granddaughter of two emperors: Frederick Barbarossa and Isaac II Angelos of Byzantium.

[39] However, the capture of Count Lara facilitated the intervention of Berengaria, who got father and son to sign the Pact of Toro on 26 August 1218, putting an end to confrontations between Castile and León.

[42] Berengaria met with the princesses' mother and succeeded in the ratification of the Treaty of Las Tercerías, by which they renounced the throne in favor of their half-brother in exchange for a substantial sum of money and other benefits.

[49] She re-established the tradition of Leónese royal women supporting the Monastery of San Pedro de Eslonza, last performed by her great-grand aunt, Sancha Raimúndez.

[50][51][52] She was also concerned with literature and history, charging Lucas de Tuy to compose a chronicle on the Kings of Castile and León to aid and instruct future rulers of the joint kingdom.