(1) The Golden Age was the era prior to glaciation. It was called thus, due to the shiny aura with which the seventy years of darkness (2) had wrapped it, in collective thinking, this idealized image of a vanished world, from which just remain legends.
(2) The Seventy years of darkness began during the global collapse, after the onset of glaciation, due to the isolation that occurred when was lost contact with Earth and the colonies became independent. This decadent period was declared unilaterally terminated by the miraculously resurrected Terrestrial Saharian Assembly, two centuries ago when they started the first door. The first thing materialized through it was a simple bunch of apples, occurred in the Olympus Base of Mars and represented a particularly significant historical event for the Martians because although they possessed underground crop fields, there were few trees and not any apple tree at all; although it was an experiment, it seemed a nice message of friendship. But soon the doors became an object of domination, when the TSA and the three terrestrial assemblies (The Australian, The Asian and American) were merged into the Confederation of Terrestrial Assemblies and monopolized its use,
which raised suspicions of former colonies, the seeds of the current situation. Then was took the moon and when the confederation became the Empire, and mistrust proved justified, although was expected a conflict, however the independent republics of Mars and Europe because of the Doors, were forced to negotiate and even collaborate with the Earth’s Empire, to the point that arguably one way or another worked for it.