The timeline in the Diablo Universe is a very scattered and non-cohesive entity. Events are rarely dated, and even when they are the dating is sparse and not necessarily conveying the entire breadth of an event.
This page is an attempt at consolidating all important events in the Diablo chronology. Events marked with clear dates have been provided by Blizzard Entertainment, and all other times are guesses inferred from their relation to known events. All events are listed in chronological order; if an event is listed below another, it happened afterwards.
- Anu was the single entity in existence and contained all good and evil. It decided to cast off all evil parts to attain total purity -- those parts become Tathamet.
- Anu and Tathamet battle for a very long time, then finally destroy each other and the Universe is created.
- The Great Evils are born from the seven heads of Tathamet. The High Heavens are created around Anu's spine the Crystal Arch, and the Burning Hells from the husk of Tathamet's body.
 Before the Sin War
- The Pandemonium Fortress is built around the Worldstone by the High Heavens.
- Inarius tires of the Eternal Conflict and seeks to flee from the constant warfare. He finds Lilith, and together with many other demon and angel rebels they steal the Worldstone.
- Sanctuary is created.
- The nephalem are born from a union of angels and demons.
- The Purge takes place. Lilith kills all angels and demons on Sanctuary other than herself and Inarius. Inarius banishes her to the void because of it.
 The Sin War
- Lilith returns to Sanctuary and begins to turn Uldyssian into her puppet to use against Inarius.
- The High Heavens find Sanctuary, and attempt to destroy it. The Burning Hells try to stop them, turning Sanctuary into a battlefield. Uldyssian pushes both armies back to their realms and destroys himself in the process.
- The Angiris Council vote on whether or not to save Sanctuary. The vote falls in Sanctuary's favor 3-2.
 Mage Clan Wars
1500 years before Diablo III
- The Mage Clan wars start and quickly lead to the Vizjerei dominating all other clans and powers through the power of their conjured demons.
- Horazon and Bartuc, two of the most powerful sorcerers at the time, battle each other. The fight destroys Viz-jun and ends in Bartuc's defeat, and the end of most of the Vizjerei.
- The mage clans scatter and become fragmented.
 The Dark Exile
- Led by Azmodan and Belial, many of the Hells' lesser demons rise up against the Prime Evils in a rebellion that culminates in the Dark Exile. Diablo, Mephisto, and Baal are exiled to Sanctuary from the Burning Hells.
- The archangel Tyrael gathers together mortal heroes to create the Horadrim. He bestows the Soulstones upon them and tasks them with tracking down and imprisoning the Prime Evils.
- Mephisto is captured near the jungles of Kehjistan and imprisoned under a Zakarum temple in what will eventually become Kurast.
- Baal is tracked to the desert near Lut Gholein. Tal Rasha, the leader of the Horadrim, sacrifices himself to capture Baal in a damaged Soulstone.
- Diablo is finally captured by a group of Horadrim monks led by Jered Cain. The monks bury Diablo's Soulstone near the river Talsande in Khanduras, and a Horadric monastery with a network of catacombs is built over the burial spot.
- The town of Tristram is established around the Horadric monastery.
- The Horadric monastery in Tristram is abandoned.
- The Horadrim, with no quests left to undertake, fade into history and legend.
 Diablo I & Diablo II
- The eastern lord Leoric comes to Tristram, declares himself its king, and converts the old, long-unused Horadric monastery to a Zakarum cathedral. His advisor, Archbishop Lazarus, secretly releases Diablo from imprisonment.
- King Leoric descends into madness as he valiantly struggles to resist Diablo's possession.
- Increasingly deranged, King Leoric begins imprisoning all who question his authority and executing them as traitors. He declares war on the kingdom of Westmarch.
- Under Diablo's influence, Archbishop Lazarus kidnaps King Leoric's only son, Prince Albrecht. The terrified child is possessed by Diablo.
- Lachdanan, captain of King Leoric's army, returns from the disastrous war with Westmarch and is forced to kill Leoric. The fallen monarch curses Lachdanan and his followers with his dying breath. Not long afterward, Lachdanan and the king's guards are attacked by Leoric, resurrected as the Skeleton King, as they attempt to bury him.
- Archbishop Lazarus leads a group of villagers into the cathedral and abandons them to a bloodthirsty butcher demon. People begin fleeing Tristram in droves.
- A lone hero arrives in Tristram and defeats the bloated, fetid butcher demon.
- The hero kills Archbishop Lazarus and defeats the Skeleton King.
- Diablo is defeated by the hero, who then tries to contain Diablo within himself. Despite the hero's noble intentions, his valiant spirit quickly succumbs to Diablo's corruption. He becomes the Dark Wanderer, leaving Tristram behind shortly before legions of foul demons attack and destroy the town and its inhabitants.
- A group of heroes begins a quest to defeat Diablo and his brothers. The heroes defeat the demoness Andariel and journey east, following the Wanderer.
- The demon lord Duriel is defeated within the tomb of Tal Rasha; it is discovered that Baal is already free from his Soulstone.
- The Dark Wanderer completes his transformation into Diablo; Mephisto is destroyed beneath the jungles of Kurast by the band of heroes.
- Diablo is defeated. His Soulstone is destroyed, along with Mephisto's, upon the Hellforge.
- Baal and his army march on Mount Arreat.
- The heroes follow Baal to Mount Arreat for the final conflict between man and the last of the Prime Evils. Although the heroes defeat Baal, his demonic army continues to advance.
- The angel Tyrael discovers that Baal has succeeded in corrupting the Worldstone housed within Mount Arreat. Realizing that the Worldstone cannot be restored, Tyrael reluctantly destroys it. The resulting explosion destroys Mount Arreat, ravages much of the countryside, and decimates Baal's army.
 Present Day
- Diablo III takes place.