Soon after the foundation of Erebonia, officials of the Septian Church were dispatched to Heimdallr to support and recognize the newly-established state. They acknowledged the legitimacy of its elected emperor, Mediator Arnor, and introduced faith to Heimdallr's citizens.
In order to provide a ceremonial site to acknowledge the legitimacy of the imperial family and to provide the citizens with a home for faith, Heimdallr started the construction of a church. The Heimdallr Cathedral was completed in S.81 under the reign of Sion Arnor, the third emperor. After its completion, Heimdallr became known as the imperial capital.
Like many Septian Church cathedrals, an underground facility known as a Primal Ground was installed. This particular Primal Ground was a reproduction of the original underneath the High Seat in Arteria. Primal Grounds are said to be artificial singularities designed to fulfil 'a certain purpose'.
Around the year S.270, Dark Dragon Zoro-Agruga appeared and attacked Heimdallr, forcing its Emperor Astorius II and citizens to flee to Saint-Arkh in the south. During the occupation, the Holy Beast sworn to protect the Sept-Terrion of Earth became corrupted by the Dark Dragon's miasma and henceforth was titled the Nameless One. The Nameless One was then sealed in the Heimdallr Cathedral's Primal Ground. The Primal Ground was then spatially translocated to an area northwest of Heimdallr beneath the site known as the Karel Imperial Villa which had been built during the Middle Ages.[Note 1]
- Patriarch Sigmar is the only known patriarch in the series to date (as of Trails of Cold Steel III). The rank of patriarch is the highest order within the church, second only to the Pope.
- Although the cathedral did not appear in-game until Trails of Cold Steel III, its bells can be heard before visiting St. Astraia Girls' School in Trails of Cold Steel, Chapter 4: "A Midsummer's Revels".
- The Heimdallr Cathedral is one year older than the Grancel Cathedral, which was built in S.82.[Note 2].
- ↑ Exact year unknown. In S.1206, Black Alberich describes the events as "900 years ago". Black Record, Volume 1 describes the disappearance of the Primal Ground as "200 years [after Heimdallr's foundation as the imperial capital in S.81]", placing these events at the start of Dark Dragon Zoro-Agruga's appearance.
- ↑ In S.1202, Bishop Reval says they "celebrate the 1120th year of the Grancel Cathedral's history".
|Dominion||Ein Selnate (1st) - Thomas Lysander (2nd) - Kevin Graham (5th) - Barkhorn (formerly 8th) - Gaius Worzel (8th) - Wazy Hemisphere (9th)|
|Knight||Rufina Argent - Abbas|
|Squire||Cesar - Juno - Marcia - Ries Argent - Rosine - Scarlet - Ventus|
|Cathedrals||Grancel - Crossbell - Heimdallr - Bareahard - Roer - Haliask - Ardent - Saint-Arkh - Ordis|
|Chapels||Bose - Rolent - Ruan - Zeiss - Trista - Celdic - Legram - Leeves - Parm - Raquel|
|Concepts||Aidios - Artifact - Gehenna - Gralsritter - Merkabah - Sept-Terrion - Stigma|