The Valian years measure the passage of time after the arrival of the Ainur in Arda. This definition of a year, named for the Valar, continued to be used during later periods. The Valian years were measured in Aman after the first sunrise, but Tolkien provided no dates for events in Aman after that point. The account in Valian years is generally not used when describing the events of Beleriand and Middle-earth.