Spring of Arda
The Spring of Arda began 1,900 years after the Valar came to Arda, after Illuin and Ormal had been raised. In that time Arda became filled with trees and herbs, beast and birds, and all the lands were green. In the midmost of Arda was the Isle of Almaren in the Great Lake where, due to the blending of the light of the Two Lamps all things were richest in grown and fairest in hue, and there the Valar made their abode and rested.
Yet beyond the Walls of Night Melkor lurked. Manwë ordained a great feast in the 3,400th year at which Tulkas wed Nessa. Afterwards Tulkas slept and Melkor, seeing his chance, passed into the North of Middle-earth and began the delving of his vast fortress Utumno. The Spring of Arda was marred as living things became sick, or rotted, or corrupted into monstrous forms. In the 3,450th year Melkor came forth in war and threw down the Lamps of the Valar, breaking the lands, roiling the seas, and ending the Spring of Arda.