How does "the poem presents guilt and it's expiation" apply to the Rime

The Mariner is unnaturally old, with skinny, deeply-tanned limbs and a "glittering eye." He sets sail from his native country with two hundred other men who are all saved from a strange, icy patch of ocean when they are kind to an Albatross that lives there. Impulsively and inexplicably, he shoots the Albatross with his crossbow and is punished for his crime by a spirit who loved the Albatross. He is cursed to be haunted indefinitely by his dead shipmates, and to be compelled to tell the tale of his downfall at random times. Each time he is compelled to share his story with someone, he feels a physical agony that is abated only temporarily once he finishes telling the tale.

Source(s): http://www.gradesaver.com/the-rime-of-the-ancient-mariner/study-guide/character-list/