Quotation from: The Chessmen of Mars

Written by: Edgar Rice Burroughs

"There are no landing-stages upon the roofs--not one that can be
seen from here; while were we looking similarly at Helium we
would see hundreds. And they have no firearms because their
defenses are all built to withstand the attack of spear and
arrow, with spear and arrow. They are an ancient people."

"If they are ancient perhaps they are friendly," suggested the
girl. "Did we not learn as children in the history of our planet
that it was once peopled by a friendly, peace-loving race?"