Another Pre-Change Myth

"'...she and I decided to run away and go on a Quest of our own; to find the Solitary Fortress of Ice where the Super Man lives.'"
-SM Stirling, The Desert And The Blade (New York, 2016), Chapter Fourteen, p. 285.

How did two Changelings know about that?

Earlier blog references:

Superman
Clark Kent - 

an immigrant with a small town upbringing;
a champion of the American Way;
a hard sf character initiating a new genre.

It is appropriate that Superman is referenced in sf. I think that Poul Anderson would have been able to write an amazing Superman novel plausibly rationalizing the Kryptonian super powers and definitively addressing issues of power and society.