He is venerated in the Roman Catholic Church as the patron saint of exorcists and those suffering from demonic possession.

Bruno was born in Cologne, Germany, around 1030, likely into the prominent Hartenfaust or Hardebüst family. Little is known about his early childhood, but he pursued theological studies at the prestigious Cathedral School of Reims, in present-day France. His education at Reims, which included classical studies and sacred sciences, earned him a reputation as a scholar learned in both human and divine knowledge.

Bruno’s desire for a life of solitude led him to seek guidance from Robert of Molesme, though he soon realized this was not his true calling. In 1084, accompanied by six companions, he approached Hugh of Châteauneuf, Bishop of Grenoble.

Bishop Hugh, who reportedly had a vision of these men as seven stars, installed them in a remote, mountainous area in the lower Alps of the Dauphiné, known as Chartreuse. There, they built an oratory and small individual cells, living in isolation, poverty, prayer, and study—thus founding the Carthusian Order.

Bruno was also a writer, composing commentaries on the Psalms and the Epistles of Paul the Apostle, which reveal his knowledge of Hebrew, Greek, and the Church Fathers. In Catholic art, he is often depicted with a skull, a book, and a cross—sometimes crowned with a halo of seven stars.