The One Ring was an artifact of great power that could control all the other Rings of Power if worn. It was created by the Dark Lord Sauron in the fires of Mount Doom in Mordor with the purpose of dominating the free peoples of Middle-earth. The hobbit Frodo Baggins was entrusted with destroying the Ring by casting it back into the fiery chasm from whence it came, in order to defeat Sauron once and for all.