When Were the Sardaukar Formalized?

Someone please let me know if this needs the Spoiler! flair, I’m always a bit confused on when something that already has ‘spoilers’ in its own flair needs that add on.

Okay! So, my memory is of Thufir Hawat in Dune telling the Baron that the origins of the Sardaukar tied directly to Salusa Secundus, but as a Prison Planet. So after some event which wrecks what otherwise looks like a really nice place to live.

Keeping that in mind, the Sardaukar probably didn’t just spring up out of nowhere. There has to have been prototypes in terms of training, organization, etc. Hawat himself even comments that the Harkonnen troops are brought up using methods that are at least barebones similar to those the Emperor must use. It’s just a matter of degree and fine tuned quality.

So are we likely to see any part of that evolution of the Imperial Guard within the time period of the Dune Prophecy series? Or does the formation not occur for several thousand years down the line?

Edit and Summary: My question is when can you say the road started in the Emperor’s levees towards the Sardaukar we have at the time of Paul? They’d existed, formally, for centuries if not millennia (I forget which). So, what was the timeline like? Can you really only talk about the final form of Sardaukar post Salusa Secundus establishment as a prison colony, or was there a corps that served as their beginning? Someone had to train the recruits they took off Secundus.

I added the above because I feel it’s more succinct and true to my intent with the questions.