Changes

Primarch [[Roboute Guilliman]], after the [[Horus Heresy]], took command of the entirety of the Imperial armed forces and took the title '''Lord Commander of the Imperium''' in order to stabilise the Imperium and begin the reforms for which he is famous. He was the only person in the history of the Imperium to control all of the Imperial armed forces (before this, the Imperial war machine was administered by the [[War Council]]). The Lord Commander of the Imperium was one of the High Lords of Terra during its use. {{Fn|6}}

===Knights of Taranis===

The [[Knights of Taranis]], a [[Knight House]] on [[Mars]], was ruled by joint commanders each known as a '''Lord Commander''' of the Knights of Taranis.{{Fn|8}}