The Golden Age was a centuries-long era in history when the human race had achieved a very prosperous existence, having colonized the entire Solar System.
Overview
The Golden Age was sparked by the arrival of the Traveler during the late 21st Century. When it arrived in the Solar System and began terraforming the different planets, humanity reached out to the Traveler on Mars and made first contact. It taught humanity new powers and mystical technologies that led to this age. Now that most of the system could support human life, and armed with the incredible new technology to reach beyond Earth, colonization of these worlds began. Many corporations and research groups existed during the Golden Age, such as Clovis Bray or the Ishtar Collective. The Exos were created during the period, and the Ahamkara appeared.
Most of the new discoveries humanity made were geared towards the colonization of the system and other vital technologies such as AI or medicine. Other technologies, and Earth itself, developed more slowly. The technology of the Golden Age has not only attracted the attention of human survivors, but also the alien races who now occupy the system. The Fallen seek to loot Venus' grand Archives, the Hive sought to use Rasputin on Earth for their own purposes, and the Cabal intended to claim the Dust Palace on Mars for themselves.
The Golden Age came to an end with the arrival of the Darkness, which began to attack humanity, and drove it back to planet Earth. The Traveler defended what was left of the human race, and through some means sacrificed itself to save humanity. The survivors of the conflict banded together and built a city underneath where the Traveler hung over the Earth. Humanity had been saved, but its golden age was over. Approximately seven hundred years from the present day, enough time has passed since the Traveler's final stand that many details about the Golden Age and how it ended, such as what, or whom, attacked and exactly how the Traveler saved humanity have been forgotten or have passed into legend.