This archive tracks four layers. A record present in 4 of them (HH, AoI, M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
chaos
Flagship of Fulgrim and the III Legion
Laid down at Jupiter as the Third Legion's primarch's ship before there was a primarch to give it to, and built twice as slowly as anything comparable because the Fabricator-General of Mars supervised it personally. The Legion's fall is staged in its own council chamber, the Heliopolis.
Position: Laeran System (Laeran) Flagship of the 28th Expedition for the Cleansing of Laeran, which is where the Legion picked up what destroyed it Cited in Fulgrim
Position: Isstvan System (Isstvan III, Isstvan V) Badly damaged the Iron Hands' flagship Fist of Iron when Fulgrim's approach to Ferrus Manus turned into a battle Cited in Fulgrim
Position: Iydris System (Iydris) Led the Emperor's Children into the Eye of Terror alongside Perturabo's Iron Warriors, to the crone world Iydris Cited in Angel Exterminatus
Position: Sol System (Luna, Mars, Terra, Titan) Back in the traitor armada for the final phase of the Solar War, with Fulgrim aboard Cited in The Solar War
Age of the ImperiumM32–M40
chaos
Crippled
At the head of the Emperor's Children fleet during the Scouring, and the deck where Fulgrim fought Guilliman and left him mortally wounded. Loyalist ships crippled it in the same battle.
Position in this era: [RECORD LOST].
The 41st Millenniumpre-Rift
chaos
[RECORD LOST]
[RECORD LOST]
nothing published places it in this era.
Position in this era: [RECORD LOST].
Era Indomituspost-Rift
chaos
Fate unknown
By M42 the Legion itself does not know whether the ship still exists. Fulgrim summons his sons to a different hull now and appears not to care.
Position in this era: [RECORD LOST].
Position
A mobile record: it carries a position timeline rather than a fixed point. The archive places it in 1 of the four eras (HH); each era section above carries that era's entry.
Books set here
4 titles in the reading tracker touch this record. Titles link out to the tracker.
wh40k.lexicanum.com/wiki/Pride_of_the_Emperor §History, cited to tracked books throughout: Fulgrim ch2/ch4, Angel Exterminatus for Iydris, The Solar War ch19 for Sol, Dark Imperium Part 1 for Thessala, Fulgrim: The Palatine Phoenix ch3
position-aoihigh
the Battle of Thessala is recorded and tracked (Dark Imperium Part 1), but Thessala is not a location in this dataset. The era is described and left unplaced rather than invented
archetypehigh
catalogue entry 16, baroque performance battleship — the reference tag is this vessel by name. The mesh lane did not build entry 16, so the record names the nearest BUILT family, 'gloriana', which is also the class canon gives it. If entry 16 is ever built this line is the only thing that needs changing