Important Dates:
Note: There is no definitive chronology of the First Age. In particular, there are several conflicting chronologies of the 500s of the First Age. These dates are based on "The Grey Annals" and "The Tale of Years" in The History of Middle-earth, vol. XI, The War of the Jewels. Other chronologies differ.
First Age:
1
Turgon arrives in Middle-earth.
50
Ulmo sends a dream to Turgon urging him to find a place to establish a realm hidden from Morgoth.
53
Ulmo appears before Turgon and guides him to the hidden valley of Tumladen.
60
Dagor Aglareb, the Glorious Battle. Siege of Angband begins.
64
The construction of Gondolin begins.
116
Gondolin is completed. Ulmo instructs Turgon to leave arms in Vinyamar for a messenger who will come to Gondolin in time of need. Turgon and his people settle in Gondolin.
316
Turgon's sister Aredhel leaves Gondolin and becomes lost and is taken in by Eol the Dark Elf.
320
Birth of Maeglin, son of Aredhel and Eol.
400
Aredhel and Maeglin return to Gondolin and are followed by Eol who is given the choice to remain in the city or be killed. Eol mortally wounds Aredhel and is thrown from the city walls to his death.