The World of Avlis

This comes up occasionally in IC posts and in game, yet for the life of me I am unable to find anything concrete on it.

Several people have said that Tolly invaded the Hills and settled there, but in my recollection, he has always been there.
Just wondered if anyone knows or has ever read anything on this topic.
If he hasn't always been there, what resided in the hills beforer Tolly?

Has this ever been addressed in the back history, or maybe even in the PnP campaign?

Just wondering if there is anything written anywhere on it.

IIRC, there's some tidbits of backstory like the Valley of the Crows that suggest the region was always populated by ogres and giant kin, but I'm not entirely sure if Tolly was always meant to be there.

The way Drem makes it sound in the old Tolly quest was that he was there amassing an army to take over Southern Avlis and that he was somehow disrupting the natural balance of the area by doing so(and hence not really supposed to be there in the first place.)

Thanks! That was more info than I was able to dig up..