The Ecclesiarchal Palace is situated on Terra. The Palace is actually a vast urban complex covering most of Terra's southernmost continent. It is the headquarters of the Ministorum, its spiritual and material home. The Ecclesiarch lives in a heavily armed and armoured fortress. The Convent Sanctorum of the Adepta Sororitas is also based within the Palace. The commander of the Convent is the Abbess of the Adepta Sororitas, who is the overall spiritual leader of the Sisterhood. She is assisted by a battle leader with the rank of Prioress.
During the Wars of Apostasy, the Ecclesiarchal Palace became the last sanctum of Goge Vandire and was besieged for many months by the a coalition of Space Marines (the Imperial Fists, Black Templars, Soul Drinkers, and Fire Hawks) and the Adeptus Mechanicus.