Consider the abstract,

> As the works of dozens of women writers have been rescued from what E.
> P. Thompson calls ***“the enormous condescension of
> posterity,”*** and considered in relation to each other, the lost
> continent of the female tradition has risen like Atlantis from the sea
> of English literature.

Taken from  -

Green,Sharon Weiner,M.A.; Wolf,Ira K.,Ph.D. (2015-02-01). GRE, 21st edition (Barron's Gre) (Kindle Locations 16724-16728). Barron's Educational Series. Kindle Edition. 

I am unable to infer the meaning of what the author is trying to suggest with this line,

> the enormous condescension of posterity

Words with their meaning- 

> ***condescension*** - an attitude of patronizing superiority; disdain.

> ***posterity*** - all future generations of people.

Kindly elaborate. I know that the author uses a metaphor(comparision) -

> the lost continent of the female tradition has risen ***like*** Atlantis