young age

Because of Violante's young age at the time of her marriage with Alfonso (she was only 10 years), she produced no children for several years and it was feared that she was barren. Alfonso almost had their marriage annulled, but they went on to have ten children:

Berengaria of Castile (1253 – after 1284). She was betrothed to Louis, the son and heir of King Louis IX of France, but her fiance died prematurely in 1260. She entered the convent in Las Huelgas, where she was living in 1284.

Beatriz (1254–1280). She married William VII, Marquess of Montferrat.

Ferdinand de la Cerda, Infante of Castile (October 23, 1255 – July 25, 1275). He married Blanche, the daughter of King Louis IX of France, by whom he had two children. Because he predeceased his father, his younger brother Sancho inherited the throne.

Leonor of Castile (1257–1275)

Sancho IV of Castile (May 13, 1258–1295)

Constanza of Castile (1258 – August 22, 1280), a nun at Las Huelgas.

Pedro of Castile (June 1260 – October 10, 1283)

Juan of Castile, Lord of Valencia (March or April 1262 – June 25, 1319).

Isabella, died young.

Violante of Castile (1265–1296). She married Diego Lopez de Haro

Jaime of Castile (August 1266 – August 9, 1284)

FROM wikipedia: Alfonso X, the Wise