Bernard, the founding abbot of Clairvaux Abbey in Burgundy, was one of the most commanding Church leaders in the first half of the twelfth century as well as one of the greatest spiritual masters of all times and the most powerful propagator of the Cistercian reform.

He was born in Fontaines-les-Dijon in 1090 and entered the Abbey of Citeaux in 1112, bringing thirty of his relatives with him, including five of his brothers—his youngest brother and his widowed father followed later. As a young abbot he published a series of sermons on the Annunciation. These marked him not only as a most gifted spiritual writer but also as the "cithara of Mary," especially noted for his development of Mary's mediatorial role.

Although he suffered from constant physical debility and had to govern a monastery that soon housed several hundred monks and was sending forth groups regularly to begin new monasteries (he personally saw to the establishment of sixty-five of the three hundred Cistercian monasteries founded during his thirty-eight years as abbot), he yet found time to compose many and varied spiritual works that still speak to us today.

Bernard died at Clairvaux on August 20, 1153. He was canonized by Pope Alexander III on January 18, 1174. Pope Pius VII declared him a Doctor of the Church in 1830.

--Source: The Modern Catholic Encyclopedia