In J. R. R. Tolkien's fictional universe of Middle-earth, the time is typically rendered in Ages. Ages are one epoch of the Valar. Before the arising of the Sun they were approximately one thousand Valian Years in length (the exact length of a Valian Year varied in different drafts of Tolkien's texts from close to 10 "Sun"-years in most versions to precisely 144 "Sun"-years in his final estimation). After the Sun, Ages "sped up" and length is more variable. The Years of the Sun began with the 30th Valian Age, and the Fourth Age of Middle-earth began with the 37th Valian Age. However, only four, not seven Ages are counted. The Second and later Ages, during the Years of the Sun, correspond more to the earlier Valian Eras than to their Ages.
Before the Ainur were made. Duration: Meaningless.
Before Eä (the universe) was made. Duration: Meaningless.
Before Arda (the world) was made. Duration: Unknown.
The earliest age of Arda, when the Valar shaped the world. Duration : Valian Years 1–~5,000 (five Ages).