The Pilgrimage was a mythological journey to the place where gods and mortals meet.[1a] It was part of the mythology of the Old Faith of Colchis, as well as featuring in countless other human cultures aross the galaxy. The Primarch Lorgar believed that because all the countless legends of divinity, from so many disparate cultures, all agree on other powers that exist beyond the veil, and that the human species' most natural instinct could not be false. It was this belief that drove him to take the Pilgrimage.[1b]
Lorgar and the XVII Legion rejoined the Great Crusade (following their reprimand at the hands of the Emperor on Monarchia) as a front for the Pilgrimage. The journey took Lorgar and the 301st Expedition Fleet across the galaxy and eventually to Cadia, where they recieved validation for their theories that all of the Old Faiths across the galaxy shared similar origins, and thus shared a universal truth. Ingethel, a native of Cadia was anointed by the gods as Lorgar's guide in revealing the Primordial Truth and undertook a ritual to do so which elevated her to the ranks of the daemonic as Ingethel the Ascended.[1c]
Ingethel the Ascended led the Serrated Sun Chapter of the Word Bearers into the Great Eye where the failure of the Eldar Empire was witnessed first hand. Ingethel informed the Word Bearers that the Eldar failed and suffered the Fall because at the moment of their ascension they were unable to accept the Primordial Truth. They gave birth to a god of pleasure and promise, yet they felt no joy.[1d] Their new god awoke to find it's worshippers abandoning it out of ignorance and fear, thus was the endless storm of the Great Eye formed, an echo of the birth-cries of the Eldar's new god.[1e] The nature of the Primordial Truth was revealed to the Word Bearers in the ashes of the Eldar Empire, they learnt that in order for humanity as a species to survive they must not commit the same sins the Eldar did, they must instead accept Chaos.
The Pilgrimage ultimately proved that the Emperor's Imperial Truth was in fact a lie and that gods truly did exist. Lorgar and the Word Bearers spent the remaining years of the Great Crusade attempting to enlighten humanity about the universal truths of the universe, swaying several Primarchs to their cause, the most notable being Horus Lupercal. When it became clear that humanity could not be enlightened without bloodshed whilst it remained shackled to the lies of the Emperor, Lorgar helped orchestrate the massacre at Isstvan V and the Horus Heresy itself.[1f]
- 1: The First Heretic (Novel) by Aaron Dembski-Bowden