His significance in the history of Spain lies in the fact that during his episcopate the church of Castile and León emerges from its isolation.
It is thought he belonged to the ancient family of the viscounts of Sédirac (also spelled Sédilhac), whose castle, southwest of La Sauvetat, still stands.
Here he was made (1080) abbot of St. Facundus at Sahagún in the diocese of León, and finally named for the archbishopric of Toledo by Alfonso VI of Castile, the great patron of Cluny.
Gregory's plans for Spain included (besides a general crusade against clerical marriage, simony, and lay investiture) the substitution of the Roman liturgy for the Mozarabic and pressure for recognition of obligations of tribute from the Spanish church.
Urban II, by raising Bernard's see to primatial dignity, gave him the power necessary to prosecute the work of Romanizing.