The Estate Imperium is a division of the Administratum described as "the million-strong records office of the Administratum." Presumably its purpose is to keep and furnish records of Imperial Adepta when they are called for by the relevant arms of the Adeptus Terra. The division's head carries the title of Chancellor of the Estate Imperium. The Estate Imperium's importance is such that its leader sometimes holds a position in the Senatorum Imperialis of the High Lords of Terra. In 945.M41, the Chancellor of the Estate Imperium was Seward Rosencranz.
- Imperial Munitorum Manual, pg. 3
- Codex Imperialis (1st Edition)