Immortality is the concept of living in a physical or spiritual form for an infinite length of time. As immortality is the negation of mortality—not dying or not being subject to death—it has been a subject of fascination to humanity since at least the beginning of known history. The Epic of Gilgamesh, one of the first literary works, dating back at least to the 22nd century BC, is primarily a quest of a hero seeking to become immortal.
