Because he initiated a campaign to eliminate Catharism

During the Middle Ages Jews were tolerated by the Catholic, although reluctantly and with a blind eye to their persecution. Muslims and so-called heretics were considered an existential threat and were never tolerated. The Albigensian Crusade and the Inquisition were the Church's response to the rise of Catharism in Spain and southern France.

The credo of the catharism is in ambiguous view of human being. The human soul, as the cathars teach, was born in Heaven of the Last drop of pure love of the Father and God's Mother and has in his inner castles the completness of Their divine compositions. But when descending on earth, the soul undergoes the adaptational remodelling by the Prince of this world. So man on earth has both the divine and diabolic potential. One of the pearls of the cathar spirituality is purification (catharsis) - to separate the divine origin and erase the presence of the opposite being.

Various religions and philosophies have explored ideas of immortality. For example, in Hinduism, there is the concept of moksha or liberation from the cycle of death and rebirth. In Christianity, the promise of eternal life is central to many beliefs. In Taoism, the focus is on achieving immortality through spiritual practices and harmony with nature.