Chaining of Melkor

The Chaining of Melkor refers to time in Arda that was free of evil and Melkor was imprisoned in the Halls of Mandos for his crimes and evils on the world.

History
At the end of the War for Sake of the Elves, Melkor's armies of darkness were defeated at the Battle of the Powers his fortress of Utumno was leveled and destroyed. Melkor, defeated was chained and bound and taken to Valinor for trail. There, he was sentenced to three ages of imprisonment in the dungeons of the Halls of Mandos by his brother Manwë, the King of Arda.

During this time, peace reigned in Middle-earth and the Elves were invited to come live in Valinor and settle outside of Cuiviénen with no evil to fear and so began their Great Journey. During this time, the Elves became a diversified people forming into many different groups and cultures. The Elves that settled in Aman became High Elves and their princes being kings. Written language systems were developed using the Sarati and the Tengwar.

In Middle-earth, the Elves developed into the Sindar rallying around Elwë (know Elu Thingol, the King of Doriath) and his Queen, the Maia Melian in Doriath. Menegroth was build. The lost group of Elves who followed Lenwë during the Great Journey reappeared in the Beleriand calling themselves the Nandor, and settled in the Ossiriand.

The Chaining lasted three ages which totaled about three thousand years. The era ended with the release of Melkor who slowly poisoned the peace and stirred up rivalries and dissent amount the Noldor. Thus, the Noontide of Valinor of Valinor came to an end and the Darkness of Valinor began and many Noldor houses rebelled against the Valar and went to war with Melkor (now Morgoth) in Middle-earth.