The Mars Of Fiction

How much do we know about it? Certain ideas float to the surface:

humanoid inhabitants

an ancient civilization on a drying planet

canals

sword

airships

a board game 

These features are common to Edgar Rice Burrough's Martian series and to SM Stirling's Lords Of Creation series. Some of the ideas also appear elsewhere. The canals on a dying planet are legendary.

How does Mars come to be inhabited?

(i) There just are native Martians.

(ii) In Michael Moorcock's ERB pastiche, Michael Kane time travels to Mars at a time before Martians had migrated to Earth.

(iii) In Lords Of Creation, technologically superior aliens terraformed Mars and transplanted Terrestrial human beings to it.

(iv) In Poul Anderson's Technic History, extra-solar aliens colonize Mars.

(v) Martians existed but are now extinct.

(vi) In works by Anderson and others, Terrestrials colonize Mars and become the "Martians."

(vii) There are even versions of Mars that were never inhabited!