Stravo wrote:
And we come to the Orks. A current Ork Codex map shows Ork Waaghs raging throughout the galaxy. Their numbers are vast. Yet in the distant past not a peep. Why didn't an Ork Waagh descend on poor hapless Earth in the 21st century? In Medieval times even? Where were the Orks?
We don't know, and frankly I think its presumptuous to think that the Orks were always as large or numerous as they are now. Alot of the factors driving Ork growth or expansion i sthe presence or absence of conflict. Back in the era you're talking there was not massive galaxy-spanning Empire which the Orks could test themselves against (YEs there were the Eldar but there's just some question to HOW vast they were. Its possible humanity was quite a bit larger.) Without anyone decent to fight the Orks are likely to turn upon themselves as anyone else.
According to most histories or chronologies they didnt start running into Orks until tens of thousands of years ago (probably around the 18th Millenium IIRC) and that was the time the humans started expanding across the galaxy. I'm also pretty sure its been mentioned before in my analysis that the Orks LOVE Humans, they're one of the best alien races they've come across to fight. And fighting the Humans for tens of thousands of years is bound to give a boost to Ork expansion and drive to win.
It's also quite possible they just didn't have access to warp drive then. Remember that Orks are more prone to looting and modifying vessels than they are of building their own by conventional means. Earlier fluff had their only means of travel being via space hulks, and given how retcons work its quite possible that Early Orks were in fact limited to this form of warp travel until they started encountering more FTL-capable races.
Then there is Chaos. Current fluff makes it seem like Chaos is banging down the front door of the Imperium. You can't throw a stone and not hit three psykers who are channelling some sort of demon threat. Yet not a peep out of Chaos during such dark times as the Mongol Invasions, WWI, WWII, Black Death. The current Chaos Space Marine Codex does make mention of a demon Prince who was creeping around on Earth since medival times but that's the only mention
Psykers didn't start cropping up in great numbers til the 18th millenium or so again (sometime in the DAoT as I remember) as did Navigators. Hell humans hadn't even started mucking about with warp travel yet. They aren't likely to be noticed or influenced by Chaos until their connections to the warp strengthen. The growth of psyker activity was in fact one of the contributing factors to the AGe of Strife.
I'm pretty sure the growing birth of slaanesh had an influence on things too, but barring that some sort of human deity/Power in the warp is likely to have existed as long as humans have, even before it manifested in the form of the Emperor.
In essence I'm asking why Earth was relatively sheltered from all of these potential threats until they started the Great Crusade?
There's millions of inhabited planets in the galaxy, possibly billions (if the Eldar or Old Ones did a great deal of terraforming) and Earth is just one of countless types. Even with huge numbers of Orks their method of warp travel is haphazard at best, and I'd say the odds of just stumbling on Earth are pretty damn high.