This archive tracks four layers. A record present in 3 of them (AoI, M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
imperium
Forge world of the Sabbat cluster
One of the manufacturing worlds that made the region worth annexing, and worth taking back.
The 41st Millenniumpre-Rift
imperium
Forge world; reconquered during the Crusade
Retaken from the Archenemy in a trench war fought across poisoned industrial flats. The Tanith First's first appearance in the record is here, disrupting a Chaos ritual in the middle of it.
Era Indomituspost-Rift
imperium
[RECORD LOST]
[RECORD LOST]
Nothing survives in the archive for Era Indomitus.
Position
Map frame: 128, 560 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 377 units ≈ 40.1k light years, west of the galactic core.
Height above the disk plane: 10.0 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Fortis Binary System
Books set here
2 titles in the reading tracker touch this record, 1 of them as a primary location. Titles link out to the tracker.
wh40k.lexicanum.com/wiki/Fortis_Binary infobox Class = Forge World; https://wh40k.lexicanum.com/wiki/Planets_(List) adds 'Reconquered during the Sabbat Worlds Crusade'
gposmedium
wh40k.lexicanum.com/wiki/Sabbat_Worlds derived: — 'a group of star systems along the edge of the Segmentum Pacificus', subdivided into the Newfound Trailing Group, the Khan Group, the Cabal Systems, the Carcaradon Cluster and the Erinyes Group. This dataset places the cluster on the rimward edge of Pacificus, anchored on Tanith and Verghast, which were already here, and gives each published sub-group its own sub-cluster. Fortis Binary is Newfound Trailing Group, placed inward of Tanith