For some of the original founding Legions we already know their original names before their Primarchs renamed them in honour of meeting with the emperor and their legion.
XII Legion originally called Warhounds later became World Eaters
XIV Legon Mortarian renamed the Dusk Raiders as the Death Guard
XVI Horus Luna Wolves were renamed The Sons of Horus
XVII Legion Lorgar's Imperial Heralds were renamed The Word Bearers.
These we know, but we know many had different names before they were reunited with their lost Primarch. If, GW were to mention the original name for your favourite Legion/Chapter (post Heresy) in some of their HH novels or in the new Forge World Heresy Era Rule Books, what would you like them to be called?
GW has a history of ret-conning many facts that do not fit in with their new design for the 40K universe, and they have used ret-conning to eliminate the Squats (never existed or were wiped out by the Tyranids). They have changed the whole history of the Necrons with the new codex. If changes like these can be done, a simple fact like mentioning the name a legion had before the primarch was introduced to them is a simple thing for GW, and can easily be re-ret-conned at a later date as GW sees fit to do, and has done in the past.
Well what do you think your favourite legion was called when the Emperor first built them and took them to the stars on his great crusade?
My favourite legion is the III Legion. The Emperor's Children. From novels and other things like the 40K Wiki and Lexicum, I have worked form the previous hinted at clues that they were drawn from the courts and blood vassal populations of Europa. Their finest youth were offered to the Emperor as tribute as penance after losing in battle at the hands of the Imperial Thunder Regiments during the Unification wars.
I thought they should be called "The Noble Sons". It suits their proud and purist dogma that they and Fulgrim held and was part of the reason for their fall to the Powers of Chaos.
The Night Lords another of my favourite legions, seems appropriate to them already, and I think in one of the HH novels it hinted at them having the same name, as the Emperor's prescience helped him in naming many of the Legions.
I would like this thread to not devolve into a troller's paradise with silly names and arguements starting. Please be civil, and when giving the name for your legion, please supply a reason why you think it should have been called the name you like.
Example: XVIII Legion - Vulcan - Salamanders - name you like them to have been called pre-crusade: Fire Lords, because they have always had an affinity with fire and flamer based weapons up until the development of melta weapons which they became their other weapon of choice.
Who knows maybe one of the GW novel writers will see your responses and add it into the HH novels.