Well, I guess you could send them back in time and put them in the middle of the Crusades. Sure, that sounds about right. Okay, now pretend that you're totally insane and figure that even whole armies aren't enough of threat - they're too mundane for such as Strange to deal with. Say you're Steve Englehart for a minute - what's the biggest threat you can think of?
If it wasn't a giant gnome, then you weren't roll-playing as Steve Englehart well enough.
Of course, you're then left in a quandary: what tops a giant gnome?
More giant gnomes. Duh.