The War of the Jewels, also known as the Wars of Beleriand, was a series of battles that the Free Peoples of the world (primarily Elves (Noldor and Sindar) and Men (Edain), plus occassionally some Dwarves (of Belegost)) stood up to Morgoth and fought against him. Many battles were fought and many lives were lost in this crusade against Morgoth, but in the end the Enemy inevitably prevailed, and it would be the host of the Valar combined with what free peoples were left in Beleriand that would overthrow Morgoth and his forces in the War of Wrath.
Battles during the War of the Jewels:
First Kinslaying at Alqualondë
First Battle of Beleriand (“The First Battle”)
Dagor-nuin-Giliath (“The Second Battle”)
Dagor Aglareb (“The Third Battle”)
Battle of the Gelion-Ascar Stockade
Dagor Bragollach (“The Fourth Battle”)
Nirnaeth Arnoediad (“The Fifth Battle”)