Why include 'real world' gods in the Realms at all? Well, that's the "Forgotten" part of the name. I envisioned a multiverse of many, many parallel worlds (alternate, side-by-side Prime Material Planes, if you prefer), with Middle-Earth, Narnia, and many other favorite fantasy settings among them, all linked together with gates. There was once much travel between them (hence our own world's legends of dragons, etc., from before the links to other places became 'forgotten'), including huge migrations...until, inevitably, power groups of sinister and formidable beings fought to control access to/use of the gates.
It's still possible (within the fiction) to travel between the Realms and Earth, as in many Dragon articles. This concept was never dropped or replaced, just deemphasized.I postulated that a high-level campaign would involve battles for control of gates/portals against shadowy 'power groups' that controlled them...which became Planescape. :} Initially, TSR downplayed the "link with other worlds" aspect because of fears of negative publicity/James Egbert/"kids doing dangerous things and blaming D&D" fears.
NiTessine said:Actually, the story I heard is that originally, they intended to put in a background story that the Realms were originally connected to own world, and in the past there was much interaction between the two worlds, which then subsided and the Realms were forgotten in our world.
However, this story was never used, because they were afraid of lawsuits if some kids went and got hurt trying to find the gate.
I am not certain where I read that, but I think it was an official source. It's been a while.