Event · M41–M42

Battle of Lion’s Gate

The Battle of Lions Gate is a conflict at the Lion’s Gate, a principal gateway of the Imperial Palace on Terra, recorded after the Great Rift opened in M41. The name belongs to one of the best-known fortified approaches to the Palace, a spaceport and gate complex on the Palace’s outer defences. It is associated above all with the Siege of Terra in the thirty-first millennium, when the Palace’s gates and bastions were the principal objective of the Warmaster Horus’s forces. Later usage attaches the same place-name to fighting on Terra after the Rift, so readers should distinguish the two periods. The setting of the M41 engagement is the Imperium Nihilus era. The opening of the Great Rift, the Cicatrix Maledictum, divided the Imperium and left Terra’s astropathic and Astronomican-dependent links to distant worlds badly strained. Warp-borne incursions, in which daemonic entities manifest in realspace, became a recurring danger on many worlds in this period. Terra, as the seat of the Senatorum Imperialis and the location of the Golden Throne, is defended by the Adeptus Custodes, the Adeptus Astartes chapters that hold garrisons there, the Adeptus Mechanicus and the Imperial Army. The Lion’s Gate, as a gateway and landing complex, is a natural point of contact between the Palace and any force arriving from orbit or from the surrounding hive districts. That is why it appears in accounts of Terra’s post-Rift defence. The details of the engagement are recorded inconsistently and should be read with caution. Accounts differ on the size of the daemonic force, the identity of its leaders and the extent of the Palace defenders’ losses. This entry does not attribute named commanders or a definite outcome to the battle. What is consistent across the tradition is the general pattern: a demonic assault on a fortified Terran gate, resisted by the Palace garrison, at a time when the Warp was more volatile than at any point since the Horus Heresy. The absence of settled detail is itself informative, since Terra’s internal affairs are among the least documented in the setting. Within the Orrery graph, the battle binds the location Terra to the M41 window that follows the opening of the Great Rift. Its neighbours are the Siege of Terra, from which the Lion’s Gate takes its fame, the Imperial Palace, the Great Rift, and the Adeptus Custodes as the Palace’s standing guardians. It should be read as a post-Rift echo of the Palace’s older defensive history, not as a repeat of the Siege. Its significance lies in showing that the heart of the Imperium is not shielded from the disorder that has spread across the wider galaxy. Captain-General Trajann Valoris was the overall commander of the Imperial defence of the Palace during the engagement. He led close to four thousand Adeptus Custodes from the Lion’s Gate against eighty-eight daemonic cohorts of Khorne, together with Grey Knights already summoned to Terra; more than half of those Custodes were killed before Roboute Guilliman’s counter-attack from Luna broke the advance short of the Eternity Gate. The battle is also called the Sack of the Lion’s Gate, the Lion’s Gate Incursion, and informally the Second Battle of Terra.

See where Battle of Lion’s Gate occurred on the galactic map in the 41st Millennium.

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