Visions of the spiritual world: A Brief Description of the Spiritual Realm, Its Different States of Existence, and the Destiny of Good and Evil Men as Seen in VisionsSundar Singh was known in his lifetime as India's most famous convert to Christianity. His twenty-three years pilgrimage as a sadhu - a wandering, penniless pilgrim - had led him across more than twenty countries on four continents. He had profoundly influenced tens of thousands of people. He never accepted the religion as such but he instead emphasized the life-changing starkness of Christ's original teachings.