Bernard of Clairvaux was a 12th-century Cistercian abbot, mystic, and influential theologian from Burgundy. After joining the Cistercian Order, he founded Clairvaux Abbey and became a central figure in the reform of the Benedictine tradition. Known for his powerful rhetoric and deep spirituality, he served as a diplomat and preacher, notably supporting Pope Innocent II during a period of papal schism and advocating for the Crusades. His theological focus on personal devotion and his significant role in spreading Marian devotion have left a lasting impact on Christian thought.