Bernhard von Clairvaux was a prominent 12th-century French monk and theologian, known for founding the Cistercian order. He played a crucial role in the reform of monastic life, emphasizing simplicity, prayer, and community living. His writings on spirituality and theology greatly influenced medieval Christianity. In addition to his monastic work, Bernhard was an important figure in the Crusades, advocating for the Second Crusade. He was also involved in church politics, helping to resolve conflicts and promote the authority of the Pope. His legacy includes numerous sermons and letters that continue to be studied today.