The name given in Gondor and the Shire to the conflict between Sauron (aided by Saruman) and the Free Peoples of Middle-earth. This took place at the end of the Third Age.

The War was fought over the Ruling Ring - Sauron wished to regain possession of it, while the Free Peoples wanted to see it destroyed. In the end, Frodo Baggins, Samwise Gamgee and Gollum made it to Mount Doom, where the Ruling Ring was cast into the flames. Sauron was defeated and disappeared. He may have been sent into the Void to join his master, Morgoth, but it is never said to where his spirit fled.
Encyclopedia entry originally written by atalante_star