While Casilda supposedly predated both Elizabeths, her hagiography was not written until three centuries after her death, and is likely influenced by the story of one of them.

[3] According to her legend, St. Casilda, a daughter of a Muslim king of Toledo, Yahya ibn Ismail Al-Mamun, showed great compassion for Christian prisoners by frequently smuggling bread into the prison, hidden in a basket concealed in her clothes, to feed them.

[5] She was raised a Muslim, but when she became ill as a young woman, she refused help from the local Arab doctors and traveled to northern Iberia to partake of the healing waters of the shrine of San Vicente, near Buezo, close to Briviesca.

[4][5] When she was cured, she was baptized at Burgos (where she was later venerated) and lived a life of solitude and penance not far from the miraculous spring.

[6] Painted between 1638 and 1642, Zurbarán's Santa Casilda used as its model a lady of the Spanish court.