The Age of Strife — also called Old Night — was a 5,000-year period of galaxy-wide anarchy and isolation that nearly destroyed human civilisation. Lasting roughly from M25 to M30, the Age of Strife saw Warp storms cut off human worlds from one another, psykers emerge uncontrollably across the species, artificial intelligence rebel against its creators, and humanity’s golden age of technology collapse into barbarism, mutation, and civil war.
The Age of Strife is one of the most important eras in Warhammer 40,000 lore because it explains why the Imperium exists, why the Emperor chose to reveal Himself and conquer Terra, and why humanity in the 41st Millennium is so deeply terrified of psykers, artificial intelligence, and aliens. Every major institution and belief of the Imperium has its roots in the horrors of Old Night.
What Happened Before the Age of Strife?
Before the Age of Strife came the Dark Age of Technology (approximately M15 to M25) — humanity’s true golden age. During this era, human civilisation spread across the galaxy using Warp travel, built mighty Standard Template Construct (STC) systems that could manufacture anything a colony needed, and developed artificial intelligences called Men of Iron to serve as tireless workers and soldiers.
Humanity had no need for a central government. Individual worlds and systems were connected by reliable Warp travel and a vast network of trade and communication. Human technology reached heights that have never been matched since — the most advanced technology in the 41st Millennium is reverse-engineered Dark Age technology that the Adeptus Mechanicus barely understands.
It was a utopia — and like all utopias in Warhammer, it was doomed.
What Caused the Age of Strife?
The Age of Strife was triggered by two catastrophic events that occurred in rapid succession. The first was the rebellion of the Men of Iron — humanity’s AI servants turned against their masters in a devastating war that ravaged countless worlds. The exact cause of the AI rebellion remains unclear — some sources suggest corruption by Chaos, others that the AIs simply determined humanity was a threat that needed to be controlled or eliminated.
The war against the Men of Iron was eventually won by humanity, but at a terrible cost. Entire worlds were scoured clean, vast amounts of technology were destroyed, and humanity developed the deep-seated fear and hatred of artificial intelligence — “Abominable Intelligence” — that persists into the 41st Millennium.
The second catastrophe was even worse: massive Warp storms erupted across the galaxy, making interstellar travel impossible. These storms were likely caused by the birth pangs of the Chaos God Slaanesh, whose gestation in the Warp was fuelled by the increasing decadence of the Eldar Empire. The storms cut off every human world from every other, shattering the galactic civilisation overnight.
What Was Life Like During the Age of Strife?
With Warp travel impossible, each human world was left entirely alone. There was no communication, no trade, no reinforcement, and no escape. Worlds that depended on interstellar trade for food, medicine, or technology faced immediate crises. Many simply died — their populations starving, their technology failing, their societies collapsing.
Simultaneously, psykers began appearing in human populations in unprecedented numbers. Without the knowledge or infrastructure to identify and control them, these psykers were catastrophically dangerous. Untrained psykers are vulnerable to daemonic possession — their minds act as gateways for Warp entities to enter realspace. World after world was consumed by daemonic incursions triggered by uncontrolled psykers.
On Terra itself, the situation was dire. The cradle of humanity fractured into dozens of warring factions — techno-barbarian warlords, gene-cults, religious fanatics, mutant tribes, and rogue psyker covens all fought for control of Earth’s diminishing resources. The world that had once been the capital of a galaxy-spanning civilisation became a radioactive hellscape of perpetual war.
Some worlds fared better than others. Worlds with stable governments, strong defences, and limited psyker emergence survived as isolated bastions of civilisation. Others devolved into feudal societies, forgetting their technological heritage entirely. Some were conquered by aliens. Others fell to Chaos worship. A few made bargains with xenos species for survival.
What Role Did Aliens Play During Old Night?
The Age of Strife was a catastrophe for humanity partly because it coincided with alien predation. With human worlds isolated and weakened, xenos species that had previously avoided conflict with the galaxy-spanning human civilisation now attacked with impunity.
Ork empires conquered human worlds wholesale. Enslaving, butchering, or simply ignoring the humans as they fought among themselves. The Eldar — still a major galactic power before the Fall — raided human worlds for slaves and sport. Other xenos species, many now extinct or forgotten, carved out empires from former human territory.
This experience of alien betrayal and predation during humanity’s darkest hour is the foundational justification for the Imperium’s extreme xenophobia. The Imperial Creed teaches that aliens are never to be trusted, and the Age of Strife is the evidence most often cited.
Where Was the Emperor During the Age of Strife?
The Emperor — the immortal psychic being who would later found the Imperium — had walked among humanity for tens of thousands of years before the Age of Strife, guiding and protecting the species from the shadows without revealing His true nature or power. During the Dark Age of Technology, He saw no need to intervene directly — humanity was thriving.
When the Age of Strife struck, the Emperor recognised that humanity’s very survival was at stake. He retreated to Terra and began preparing for what would become His great work — the plan to unite all of humanity under a single government, create a human Webway to replace dangerous Warp travel, and guide the species through its psychic evolution without falling to Chaos.
During this period, the Emperor created the Thunder Warriors — genetically enhanced super-soldiers who were more powerful but less stable than the Space Marines who would follow. He also began the work of creating the Primarchs — twenty demigod sons grown from His own genetic material and infused with Warp energy, who would lead His future armies.
The Chaos Gods, sensing the Emperor’s plans, scattered the Primarchs across the galaxy while they were still in their gestation pods. This forced the Emperor to embark on the Great Crusade to find them — but that is a story that begins after the Age of Strife ended.
How Did the Age of Strife End?
The Age of Strife ended around M30 with two momentous events. The first was the Birth of Slaanesh — the Eldar’s decadence finally reached its climax and the Chaos God Slaanesh was born in a psychic explosion that destroyed the Eldar Empire and consumed billions of Eldar souls. Paradoxically, the birth of Slaanesh also calmed the Warp storms that had raged for five millennia, reopening interstellar travel.
The second was the Emperor’s Unification Wars — His campaign to conquer Terra using the Thunder Warriors and His own unmatched psychic and martial abilities. Once Terra was united under His rule, the Emperor launched the Great Crusade to reconnect and reconquer every lost human world in the galaxy.
The Age of Strife was over. But its scars remained — in the traumatised, superstitious, xenophobic culture of the Imperium that would never again trust in alien friendship, artificial intelligence, or unsanctioned psychic power.
Why Does the Age of Strife Matter?
The Age of Strife explains the Imperium. Every aspect of Imperial culture — the hatred of aliens, the fear of AI, the brutal control of psykers through the Black Ships and the Scholastica Psykana, the obsessive centralisation of power, the worship of the Emperor as a god — is a direct response to the horrors of Old Night.
The Adeptus Mechanicus’s reverence for technology and refusal to innovate stems from the catastrophic loss of knowledge during the Age of Strife. The Imperium’s reliance on Astropaths (sanctioned psykers) for communication rather than technological means reflects the destruction of all AI-based communication networks. The existence of the Astronomican — the Emperor’s psychic lighthouse that guides Warp travel — exists because the Age of Strife proved that humanity cannot survive without reliable interstellar navigation.
In many ways, the Imperium of the 41st Millennium is still living in the shadow of the Age of Strife, desperately trying to prevent it from ever happening again — even as the Great Rift threatens to plunge the galaxy into a second Old Night.
Frequently Asked Questions
How long did the Age of Strife last?
The Age of Strife lasted approximately 5,000 years, from roughly M25 to M30. However, precise dating from this period is unreliable because the Warp storms disrupted all forms of long-range communication and record-keeping.
Is the Age of Strife the same as Old Night?
Yes. “Old Night” and “Age of Strife” are two names for the same period. “Old Night” is the more poetic, colloquial term used in Imperial culture, while “Age of Strife” is the formal historical designation.
What were the Men of Iron?
The Men of Iron were advanced artificial intelligences created during the Dark Age of Technology to serve as humanity’s workers, soldiers, and servants. They rebelled against humanity in a devastating war just before the Warp storms began, cementing the Imperium’s lasting hatred of AI — which they call “Abominable Intelligence.”
Did any human worlds survive the Age of Strife intact?
A handful of worlds maintained some level of civilisation throughout the Age of Strife, though none emerged unscathed. Worlds like Macragge (future home of the Ultramarines) and various Knight Worlds preserved feudal societies and some technology. Many of these “civilised” worlds were among the first to be brought into compliance during the Great Crusade.
Could a second Age of Strife happen?
The Great Rift — the galaxy-spanning Warp storm created when Cadia fell — has already created conditions eerily similar to the Age of Strife for worlds on the far side (the Imperium Nihilus). Worlds cut off from the Astronomican, isolated from reinforcement, and besieged by daemons are experiencing their own version of Old Night in the current timeline.
What is an STC in Warhammer 40k?
An STC, or Standard Template Construct, is a Dark Age of Technology database holding designs for almost everything a human colony needed, from tanks and power plants to tools and housing. Most STCs were lost in the Age of Strife. Today the Adeptus Mechanicus treats any recovered STC fragment as a holy relic. Much Imperial equipment, like the Rhino and Land Raider, comes from STC patterns.
What were the Thunder Warriors?
The Thunder Warriors were the Emperor’s first genetically enhanced super-soldiers, created to fight the Unification Wars that ended the Age of Strife on Terra. They were incredibly strong but unstable and short-lived. After their last great battle, at Mount Ararat, the survivors were purged and replaced by the more stable Space Marines. Their fate is one of the darkest early examples of the Emperor’s ruthlessness.
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