: "If you go back further, then there are nine kingdoms, and 12 kingdoms.
"Eventually you get back to where there are a hundred kingdoms — petty kingdoms — and that’s the era we’re talking about here."
So far back will the prequel be set that some of GoT's most famous families will not yet exist.
Martin said that while the Starks will certainly exist in ancient Westeros - the Lannisters will not have been formed yet.
He explained: "The Starks will definitely be there.
"The Lannisters aren’t there yet, but Casterly Rock is certainly there."
MAMMOTHS ROAM WESTEROS
Martin, who is executive producer on the prequel, also revealed there will be a host of pre-historic beasts roaming Westeros.
He said that mammoths, direwolves and White Walkers will dominate the landscape - but there will be no dragons.
In terms of similarities, the new spin-off will still feature a large ensemble cast rather than focusing on a few lead stars.
Martin said: "For Game Of Thrones, we never even nominated anybody for lead actress or lead actor until recently.
We don’t have leads so much as a large ensemble cast
George R R Martin
"It was always for supporting [categories] because the show is such an ensemble.”
He added: “I think that will be true for this show too.
"We don’t have leads so much as a large ensemble cast."
Those confirmed by HBO among the large new cast include Naomi Watts, Miranda Richardson, Naromi Ackie and Denise Gough.
While the new show's title is still top secret, Martin said he is tempted by the name "The Long Night".
He is still open to ideas though.
Martin explained: "I heard a suggestion that it could be called ‘The Longest Night,’ which is a variant I wouldn’t mind - that would be pretty good."
But regardless of the new name, he doesn't expect the prequel to live up to the earth-shattering success of its forerunner.
Appearing on the Maltin On Movies podcast, Martin said: "The scale of ‘Game of Thrones’s’ success... it’s not something anyone could ever anticipate, not something I expect to ever experience again."
Tamar Hassan appears as a Dothraki Khal in legendary Game Of Thrones scene when Daenerys destroys the ‘Temple of the Dosh Khaleen’
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