- "There can be but one Emperor, one God, one Saviour, one Deliverer. Without Him, a billion billion souls are nought but fodder for the ever-thirsting evils of the Warp."
- — Ecclesiarch Theodacus V, Indroit to the Verses of Dusk
The Ecclesiarch is the nominal High Priest of the Imperial Cult and the chief administrator of the Adeptus Ministorum. Elected for life by the Holy Synod, a gathering of the most prominent Cardinals of the Imperium of Man, the Ecclesiarch primary duties are to represent the Ecclesiarchy as one of the High Lords of Terra in the Senatorum Imperialis, to order the launch of Wars of Faith, and to monitor and maintain the devotion of the average Imperial citizen to the orthodox worship of the God-Emperor of Mankind. Since the establishment of the Imperial Cult as the state religion of the Imperium in the 32nd Millennium, the Ecclesiarch has always held a position as one of the High Lords of Terra and has maintained a highly influential seat on the Senatorum Imperialis, at times acting as the Imperium's most politically powerful High Lord. The Ecclesiarch rules the Imperial Cult's galaxy-spanning priestly hierarchy from the massive, continent-sized Ecclesiarchical Palace on Terra, which is one of the most popular sites for pilgrimage in the whole Imperium. On a related note, in many Low Gothic dialects, the term "Ecclesiarch" is used honorifically to refer to the most senior Ministorum priest of a given parish, as he or she is the local authority on matters of faith.
There have been close to 600 individuals who have borne the title of Ecclesiarch since the inception of the Imperial Cult as the Imperial state religion in the 32nd Millennium. The following short list contains the most (in)famous of those to occupy the Ecclesiarchal Throne on Terra:
|Name||Notable Feats||Cause of Death|
Ecclesiarch circa 200.M31, Veneris II was elevated as the first Ecclesiarch of the Imperial Cult to become a member of the Senatorum Imperialis.
Ecclesiarch during the 34th Millennium, Benedin IV announced in 200.M34 that the central seat of power of the Ecclesiarchy would be moved to Ophelia VII, distancing himself from the Senatorum Imperialis.
Ecclesiarch during the 34th Millennium, in 300.M34, Greigor XI announced that the Adeptus Ministorum's seat of power would return to Terra which increased Ecclesiarchial control of the Senatorum Imperialis. Many objected, but even after his death under mysterious circumstances, the planned move still transpired.
Ecclesiarch during the 35th Millennium, infamous for corrupting members of the Officio Assassinorum and employing Assassins to eliminate several recalcittrant governors, cementing the Ecclesiarchy's power over the rest of the Imperium.
Ecclesiarch at the beginning of 36th Millennium, an utterly incompetent non-entity who was controlled and finally overthrown in a bloodless coup by the Master of the Administratum, Goge Vandire.
Executed as Heretic
Ecclesiarch at the beginning of 36th Millennium, and also Master of the Administratum, he engineered the ascension of the degenerate Ecclesiarch Paulis III. Shortly after, Vandire topples Paulis and assumes the mantle of both High Lord of the Administratum and Ecclesiarch. Vandire's Reign of Blood begins. Almost 14 billion are slaughtered by the Divine Army during the Purge of Lastrati. The Daughters of the Emperor from San Leor are coopted into becoming Vandire's personal bodyguard, and are renamed the Brides of the Emperor. The Reign of Blood culminates in the Siege of the Ecclesiarchal Palace, at the height of which High Lord Vandire is executed by Alicia Dominica, the leader of the Brides of the Emperor.
Executed as Heretic
|Sebastian Thor||Ecclesiarch during the 36th Millennium, led the revolt against Goge Vandire and was promoted in his stead. Promulgated reforms including the Decree Passive and the creation of the Adepta Sororitas. Acclaimed as Saint and greatest Ecclesiarch ever. In 350.M36, Sebastian Thor returns to Terra for the last time, and passes away six months later at the age of 112. The entire Imperium mourns his passing, and he is declared a saint.||Old Age|
|Equitus XI||Successor of Sebastian Thor during the mid 36th Millennium. Reinstated the tradition of taking an Ecclesiarchal name. Finalized Thor's reform and the organisation of the Adepta Sororitas, creating the convents and formalising the position of Abbess to lead the convents. He appoints Sister Palmiro of the Order of the Holy Word to the position.||Old Age|
|Alexis XXII||Ecclesiarch of the late 36th Millennium. Split the existing Convent Sanctorum and Convent Prioris of the Adepta Sororitas into two convents each.||Unknown|
|Deacis VI||Ecclesiarch during the mid-38th Millennium. Split the existing Convents further, spreading the influence of the Adepta Sororitas to the furthest reaches of the Imperium. The Order of the Bloody Rose is founded at the Convent Sanctorum in honor of Saint Mina. The Order of the Sacred Rose, founded in memory of Saint Arabella, the last of the six sisters to enter the Throne Room, is formed at the Convent Prioris.||Unknown|
|Inovian III||Ecclesiarch during the 39th Millennium. Canonised the Heroes of the Redemption Crusades as Imperial Saints, living incarnations of the Emperor's will.||Unknown|
|Umberto II||Ecclesiarch during the 39th Millennium. First Ecclesiarch since Goge Vandire to reaffirm the authority and power of the Adeptus Ministorum over the Imperium, and he worked tirelessly to promulgate the Imperial Faith across the human-settled galaxy. Revered as an Imperial Saint and buried on the Cemetery World of Certus Minor.||Unknown|
|Decius XXIII||Current ruling Ecclesiarch, famous for repeatedly clashing with the Inquisition.||Currently in office|
- Codex: Sisters of Battle (2nd Edition) pg. 6
- Codex: Witch Hunters (3rd Edition)
- Dark Heresy: Blood of Martyrs (RPG), pp. 8-15, 35-36, 41
- Warhammer 40,000 Rulebook (6th Edition), pg. 171
- Legion of the Damned (Novel) by Rob Sanders
- The Emperor's Finest (Novel) by Sandy Mitchell