History of Arda

In J. R. R. Tolkien's legendarium, the history of the fictional universe of Eä began when the Ainur entered Arda, following the creation events in the Ainulindalë and long ages of labour throughout Eä, the universe. Time from that point was measured using Valian Years, though the subsequent history of Arda was divided into three time periods using different years, known as the Years of the Lamps, the Years of the Trees and the Years of the Sun. A separate, overlapping chronology divides the history into 'Ages of the Children of Ilúvatar'. The first such Age began with the Awakening of the Elves during the Years of the Trees and continued for the first six centuries of the Years of the Sun. All the subsequent Ages took place during the Years of the Sun. Most Middle-earth stories take place in the first three Ages of the Children of Ilúvatar.

Music of the Ainur

The supreme deity of Tolkien's universe is called Eru Ilúvatar. In the beginning, Ilúvatar created spirits named the Ainur from his thoughts, and some were considered brothers or sisters. Ilúvatar made divine music with them. Melkor, who was then the most powerful of the Ainur, broke the harmony of the music, until Ilúvatar began first a second theme, and then a third theme, which the Ainur could not comprehend since they were not the source of it. The essence of their song symbolized the history of the whole universe and the Children of Ilúvatar that were to dwell in it — the Men and the Elves.