Abbot of Clairvaux. In 1112 he entered the monastery of Cîteaux and three years later was sent to establish a new house at Clairvaux. He came to exercise an immense influence in ecclesiastical and political affairs. In 1129 at the Synod of Troyes he obtained recognition for the Rule of the Templars, which he is said to have drawn up. In the disputed Papal election in 1130, he secured the victory of Innocent II; his relation with the Papacy became even closer with the election of a Cistercian monk and former pupil as Eugenius III in 1145. In his last years Bernard preached the Second Crusade.
His best-known work is the unfinished series of sermons on the Song of Songs. In it he ranges from the practical life of the monk to the mystical confrontation between the bridegroom and the bride of the Canticle; by use of allegory he interprets the bridegroom as Christ and the bride sometimes as the Church, sometimes as himself. Other sermons convey his deep-felt devotion to the BVM. Various treatises single out particular themes of the ascetic life. His letters show his concern with political and moral matters. They did much to prepare and then secure the condemnation of Peter Abelard at the Council of Sens (1140). Bernard sought to limit the use of reason in theology, and in his denunciation of the luxury of the Cluniac way of life to defend the ascetic ideal. In his opposition to the persecution of the Jews, he stood out from his contemporaries. Feast day, 20 Aug.