Stephanie was born at an unknown date, and is first recorded as wife of García in a document dated 1038/40. The Chronicle of Saint-Pierre-le-Vif would make Stephanie wife first of Roger I of Tosny, then of García, and sister of Ramon Berenguer I, Count of Barcelona and hence daughter of Berenguer Ramon I, Count of Barcelona. This would call for prohibitively tight chronology, and does not fit with Roger's known widow, Godehildis, marrying a Norman lord. Adémar de Chabannes has Roger marrying an unnamed daughter of Ermesinde of Carcassonne, widow of Ramon Borrell, count of Barcelona and mother ofBerenguer Ramon I, but he makes no mention of Roger's wife then marrying García. It is uncertain if the Chronicle misplaced Stephanie by a generation or was mistaken in identifying Roger's wife with the later queen of Navarre. French historians of Languedoc tend to see García's wife as daughter of Ermesinde's brother Bernard-Roger, Count of Bigorre and his wife Garsenda, and thus sister of Gerberge, wife of Ramiro I of Aragón.
Possible first marriage
There are other hints, besides the dubious account of the Chronicle of Saint-Pierre-le-Vif, to an earlier marriage by Stephanie. Histoire Générale de Languedoc, giving no quote or source reference, reports the existence of a 1036 marriage contract attributed to Stephanie. An episode related in the Chronica Naierensis tells that a daughter of queen Stephanie by a prior husband was promised as wife to Sancho II of Castile, but she was abducted and married by an illegitimate son of García. Jaime de Salazar y Acha suggests that this represents the authentic account of the marriage of García's bastard son, Sancho Garcés, Lord of Uncastillo, to his wife Constanza, though traditional accounts give her different parentage. He recognizes the problem with identifying the father with Roger I of Tosny and follows an alternative reconstruction that would make the Iberian crusader a distinct Roger de Tosny, nephew of Roger I.
Issue
Stephanie had the following children by García:
Sancho IV "El de Peñalén", king of Navarre, married Placencia
Ramiro, lord of Calahorra
Ferdinand Garcés, lord of Bucesta
Raymond Garcés "the Fratricide", lord of Murillo and Cameros