August 20 is the feast day of St. Bernard of Clairvaux (1090-1153), one of the great monastic leaders and theologians in the history of the Church. The feast is also observed by many churches within the Anglican Communion, including the Episcopal Church, and by the Evangelical Lutheran Church in America.

Although born to an aristocratic family in France, Bernard left his comfortable life behind and, at age 22, entered a poverty-stricken monastery at Cîteaux, located just a few miles south of his family's estate. He is said to have persuaded about 30 of his relatives and friends to join him, but we don't know how many of them endured as Bernard himself did.

Three years later he was elected abbot of a newly-established monastery at Clairvaux, a position he would hold for most of the remainder of his life. He later admitted that he was at first too strict on his fellow monks, but he adjusted to reality in due course.

Clairvaux prospered, establishing other foundations in France, Britain and Ireland. By the time of Bernard's death, there were some 700 monks at Clairvaux alone.

Like many clerical figures even today whose original vocation was to the monastic or quasi-monastic life (Cardinal Sean O'Malley of Boston and the retired archbishop of Milwaukee, Rembert Weakland, come immediately to mind). Bernard was often drawn away from his life of prayer and solitude into the public life of the Church.

Thus, after a bitterly disputed papal election in 1130, he became an active and relentless advocate for the claims of Innocent II against Anacletus, regarded only in hindsight as an antipope. The post-election schism lasted some eight years. Because of the support Bernard had rendered throughout the schism, Innocent II bestowed his own support in return on Bernard's Cistercian order, which grew rapidly thereafter.

In 1145 Bernard's former pupil and fellow Cistercian was elected pope, taking the name Eugenius III. Bernard thought him too young and inexperienced to assume such a lofty responsibility, but once installed in office, Eugenius III enjoyed Bernard's full support and assistance --- so much so that some accused Bernard of being himself the pope rather than Eugenius.

Although he was renowned for his extraordinary sanctity even during his lifetime, and was formally canonized only 21 years after his death, Bernard, like all other saints, had his faults. His tended to be magnified, however, because of his frequent forays into the public arena.

He was too quick to condemn reputable scholars like Peter Abelard and Gilbert de La Porrée, the bishop of Poitiers, for their theological views. He criticized other monastic foundations, including the famous reformed monastery of Cluny, for what he considered their luxuriant ways. And he intervened in episcopal elections in various European dioceses.

He also devoted much time and energy in preaching against a rigorist sect, the Cathari, or Albigensians, in southern France, but he achieved little lasting success. Later, at the explicit request of Pope Eugenius III, he traveled throughout northern Europe in support of the Second Crusade to liberate the kingdom of Edessa (in modern-day Turkey) from the Muslims.

That Second Crusade, however, ended in total failure and many blamed Bernard because he had become so closely identified with the cause.

On the other hand, when Bernard devoted himself to what he was clearly best at, namely spiritual and theological writings, he was far more successful.

Among his many works were his 86 sermons on the Canticle of Canticles (also known as the Song of Songs), which reflected on the practical side of monastic life as well as the mystical union between Christ and the Church.

His final years were devoted to another project requested by his fellow Cistercian, Eugenius III. Entitled De Consideratione ("On Consideration"), it was intended as a comprehensive reflection on papal spirituality --- or, one might say, "How to be pope while remaining a committed disciple of Jesus Christ." To be sure, not all incumbents, including Eugenius III himself, have successfully followed all of Bernard's advice.

Upon completion of the treatise, Bernard was once again drawn into the public forum, serving as a mediator between the forces led by the duke of Lorraine and the inhabitants of Metz. By now, however, his health had seriously deteriorated, and he died soon after his return to Clairvaux.

Bernard was declared a Doctor of the Church in 1830, one of just over 30 such saints who have been designated as eminent teachers of the faith. Because of his eloquence in preaching, he was also given the unofficial title, Doctor mellifluus ("Mellifluous Doctor"). Pope Pius XII devoted an encyclical to him under that same title in 1953.

Fr. Richard McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame.