The Millennial Calm is an era of Ealdremen's history referring to roughly a thousand years without major warfare between its primary interstellar political powers. The span of the Millennial Calm is generally agreed to begin in 3045 CGC at the earliest, which was the end of the Second Imperial-Alliance War, and to end in 4100 CGC at the latest with the Watershed. Historians debate over the precise dates that the Millennial Calm began and ended, as the official end of the Second Imperial-Alliance War did not necessarily end all conflict related to it.
Because of the general peace throughout Ealdremen, the Millennial Calm is predominately characterized by its rapid advancement across sciences and disciplines, predominately engineering and magic science. Devices, spells, and samples of scientific literature dating to this era's latter years consequently are typically more advanced than anything from after the Watershed, but they may not always be accessible for one reason or another; since the end of the Millennial Calm, the means to maintain technology from this period have become increasingly difficult, and some languages have even gone entirely extinct, preventing the accurate translation of some literature from the period.