Eras
The great epochs that carve up the history of Warhammer 40,000: the ages, crusades, and cataclysms that shaped the setting.
~60 Million Years AgoThe War in Heaven
A primordial galactic war between the deathless Necrons and their C'tan star-gods and the ancient Old Ones and their servants, which scarred the galaxy forever.
M15–M25The Dark Age of Technology
Humanity's golden age of interstellar expansion and boundless science, when mankind mastered the stars before hubris and rebellion brought it crashing down.
M25–M30The Age of Strife
Five thousand years of isolation, warp storms, and horror when the tides of Chaos cut Terra off from the stars and humanity nearly perished.
M30–M31The Great Crusade
The Emperor's grand campaign to reunite the scattered worlds of humanity beneath a single enlightened rule and cast down the darkness of superstition.
M31The Horus Heresy
The galaxy-spanning civil war in which the Warmaster Horus turned half the Emperor's Legions to Chaos and brought the Imperium to the brink of ruin.
M31–M32The Scouring
The bitter aftermath of the Heresy, when the victorious loyalists hunted the broken traitor Legions into the Eye of Terror and beyond.
M32–M41The Age of the Imperium
Ten thousand years of grinding war, dogma, and slow decline as the Imperium hardened into a xenophobic theocracy ruling a million worlds by faith and fear.
Late M41The Time of Ending
The apocalyptic close of the forty-first millennium, when every ancient enemy stirred at once and the galaxy seemed poised to fall into final darkness.
M42The Era Indomitus
The present age of the sundered galaxy, split by the Great Rift, defended by the reborn Primaris legions and the returned primarch Roboute Guilliman.