Cristina Bermúdez was an infanta of León, daughter of King Bermudo II and his first wife Queen Velasquita Ramírez. On her father's side, her grandparents were Ordoño III and Queen Urraca Fernández, daughter of count Fernán González of Castile. Her grandparents on her mother's side were most probably Count Ramiro Menéndez and his wife Adosinda Gutiérrez, both members of the highest Galaico-Portuguese nobility.

Bermudo II, called the Gouty, was first a rival king in Galicia (982–984) and then king of the entire Kingdom of León (984–999). His reign is summed up by Justo Pérez de Urbel's description of him as "the poor king tormented in life by the sword of Almanzor and in death by the vengeful pen of a bishop," Pelagius of Oviedo, half of whose Chronicon covers the reign of Bermudo and is highly critical of the king. He accuses Bermudo of imprisoning Bishop Gudesteus of Oviedo in the 990s and blames the attacks of Almanzor on Bermudo's sins.