According to the "Historia silense", the eldest child of Ferdinand I and Sancha, a daughter called Urraca, was born when her parents were still Count and Countess of Castile, so her birth could be placed in 1033–34. The second child and eldest son, Sancho, must have been born in the second half of 1038 or in 1039. The third child and second daughter, Elvira, may have been born in 1039–40, followed by Alfonso in 1040–41, and finally the youngest of the siblings, García, sometime between 1041 and 24 April 1043, the date on which King Ferdinand I, in a donation to the Abbey of San Andrés de Espinareda, mentions his five children. All of them except Elvira signed a document in the monastery of San Juan Bautista de Corias on 26 April 1046.