In another thread this comment made me want to read about the Black Templar again. I love the old lore so any excuse to read up a bit again is a good one

"No, earlier edition BT have been explicitly some of the last remnants in the Imperium that remembered the Imperial Truth, sharing that with probably only the primarchs, the Custodes and the deep records of Mars. That was a huge and unique part of their identity - that despite the whole "religious crusader window dressing" they were ostensibly atheist of the "the Emperor is but a MAN" (The post has since been deleted so I don´t write the username)
I don´t really remember that picture but since I have not read much of the BT background since their WD Index Astartes article, I got curios and had a look in the books I have at home.
First up is Codex Armageddon, 3rd Edition (2000)
Not much in this one; Sigismund takes command of the BT and to prove his loyalty to big E, began the greatest crusade in the history of the Imperium. They have no home worldbut are fleet based. In their special rules can see some description of their overall traits.
- They have a Righteous Zeal (they are really angry and advance instead of falling back)
- Unique BT squad (they don´t conform to the codex astartes)
- Conviction that big E will save them (they don´t take cover)
- They don´t like unclean people or witches or warlocks (bonuses to hurt those people)
Not a lot of fluff here but here is the core of the BT is shaping up.
Next up is the Index Astartes II (2003)
Here the BT is a little more fleshed out; Sigismund is chosen to lead the BT for his fervent faith in big E and his undying devotion to humanity. The BT faith is described as fanatical even rabid in their lust to crush the enemies of mankind. In the Index their uniqueness is that they have been crusading for 10.000 year to prove trier loyalty, their difference from the codex organization and the Emperors champion. They are fanatical in their zeal to stomp on the mutant, heretic and psykers and will mercilessly wipe out populations of worlds to expunge the sin of heresy.
- So here we have a more complete description of the BT. There is no mention that they are religious but that is not unique since practically all chapters sees big E not as a god but the ultimate human. There is no mention of them upholding the Imperial Truth in any special way either.
Codex Black Templars, 4th Edition (2005)
Now the BT gets a lot of fluff and I will try and sum it up as best as i can

In the introduction it is repeated that Sigismund is chosen as the Emperors champion for his fervent faith in big E and his undying devotion to humanity. To prove their loyalty the start the longest crusade in the history of the Imperium. The warriors that became the BT is seeking to follow his example. They have no tolerance for heretics, mutants, warlocks, aliens or any other abominations against big E and are utterly ruthless against anything perceived as a threat to the Emperor. The BT is described to be super righteous, fanatical and furious.
There are some more religious loaded words in the codex like; sacred revulsion at the foe; the holy bolter as divine instrument of big E; the embodiment of the sacred flesh of the Emperor; holy relics. But as a hole the BT is not portrayed as a religious chapter or that they have a religious appearance, their singular faith is for their duty. No mention in the codex that they, in contrast to other chapters, follows the old Imperial truth.
- In summary the first BT codex paint the same picture as the index two years earlier. The fluff is vastly expanded but the unique traits of the BT have stayed the same.
Dataslate Reclusiam Command Squad (2013)
Here the special BT reclusiam command squad, High Hand of the Emperor, is described fervent prayers to the Emperor and his sacred word.
- A shift to a more religious leaning?
Codex Space Marines, 7th Edition (2015)
Just a brief description that they have always fought to uphold the honor of the Emperor, and of Dorn and that they are a fleet based crusading chapter.
The new unique thing about the BT is "the Black Templars’ absolute conviction, in contrast to all other Space Marine Chapters, that the Emperor is a god".
- Nothing to contradict the old picture except that the religious bit is brand new thing (or at least from 2013).
Codex Space Marines, 7th Edition (2017)
In the new codex there is a very short picture of the BT. They are a fleet based crusading chapter. As pious champions of the Emperor, their fanatical devotion has driven them to deliver righteous retribution against every traitor, alien and daemonic abomination they have faced in battle. The BT faith in the God-E is consider fanatical. Face-to-face with his enemy, a Black Templar can fight with the noblest ideals of honor, earning glory and respect as he ensures that each of his foes is truly vanquished.
- Here is in my opinion the biggest departure from the previous lore that focused on the BT as fanatical (angry) marines that utterly zealous hated all enemies of big E. Before there was no ideals of honor, just of ruthless stomping on the foes. There is also more focus om the religious nature of their faith.
So in summary I must say that I can´t find any description of the BT as "some of the last remnants in the Imperium that remembered the Imperial Truth, sharing that with probably only the primarchs, the Custodes and the deep records of Mars".
Neither is the Black Templars more "ostensibly atheist" than any other chapter in the older lore.
Lastly, I don´t see that BT had any "religious crusader window dressing". They seems to go from a non religious chapter, as any else, to super religious in 7th Edition. Maybe there is a point to make that the term crusading evokes the religious crusaders in our own time but that´s not supported in their background.
- Have I misses something important?
As you can see above I do not have any novels with the BT, and perhaps they give a different picture?
Personally I must say that I liked the older BT lore better than the new one, but fictitious religious nut-jobs can also be fun so I absolutely see that the new BT can appeal to many people also.
(Above is of course just my personal opinions and should be taken in that spirit
