- Alchemy was used to drive civilization in this era. However, it was used for war and was soon sealed away by a group of Sages to prevent worldwide destruction. All the elements below were permanently affected:
- The landmass of Weyard was much more uniform and in the shape of a crescent moon, with an island landmass to the east of the main landmass. This mass started breaking up and sinking into the oceans with Alchemy's departure.
- Great civilizations, including a far more grand version of Lemuria, as well as the earthbound city of the Anemos, colonized the world as driven by the force of Alchemy's powers. Lemuria traded with many continents on the mainland supercontinent. The Ankohl may have also been a civilization towards the end of this era. Ruins from these civilizations can be found around Weyard in the form of the Elemental Lighthouses, Sol Sanctum, Altmiller Cave the strange tiled room at the bottom of Altin Mines, the Anemos Sanctum, Madra Catacombs, the Islet Cave and the Ankohl Ruins.
- Poseidon is described by the old man at the Sea of Time Islet as the "once true rightful king of the seas". Poseidon was evidently a more sentient, gentle being in this era.
- The current king of Lemuria, Hydros, is currently the only known character in the modern age to have been alive during the ancient past. It would be quite easy to figure Hydros was a representative and/or figurehead of Lemuria during this time period. The fact he has been alive since the ancient past over the ages has led him to be the only one to directly observe how the world effectively stands still and begins to gradually wane following the seal of Alchemy. This is why in the modern age, Hydros has formed the belief that Alchemy is the lifeblood of the world and that the world will eventually deteriorate to nothing if Alchemy is not brought back. The player may also visit an area called "Ancient Lemuria", where dilapidated, abandoned ruins hearken back to the grandeur of the past and the creeping deterioration of Weyard's civilization.
- The myth of Hoabna and Yegelos recounts a series of events and conflicts between the settlements that were the ancient equivalent to modern-day Contigo and Shaman Village. While these were in conflict, the hero of Shaman, Hoabna, waged many personal conflicts and competitions with the hero of Contigo, Yegelos, and they clashed many times in modern-day Trial Road. The two eventually became great friends, however, along with their respective home settlements, and to signify this Hoabna gave Shaman Village's Shaman's Rod to Yegelos while Yegelos gave Contigo's Hover Jade to Hoabna for mutual safekeeping over the generations.
Golden Sun: The Lost Age provides a general overview of Weyard as it existed in the ancient past; it is the Lost Age of Man that the game's title alludes to. In this age, the ability to use Alchemy and Psynergy was unfettered and accessible to the general populace, and civilization had reached great levels of development. Various clans of Adepts existed across Weyard, and the landmasses of Weyard itself were far more uniform: It generally resembled the shape of a giant crescent moon. The four Lighthouses were lit at this time, providing energy to both the world and the people.
As the story goes, conquest and war eventually became objectives amongst those who desired power, riches, and dominion over all that lived, and global war fueled by the misuse of Alchemy for military purposes yielded potentially catastrophic results for Weyard; the world would have been torn apart if not for the efforts of a group of brave and wise men who took it upon themselves to seal Alchemy away by removing the Elemental Stars from the four Lighthouses, and confining the jewels in the innermost reaches of Mt. Aleph's Sol Sanctum. The world and the people were saved from themselves, but deprived of a massive resource, and Alchemy and the four Lighthouses would remain dormant for ages to come.
With the sealing of Alchemy, Weyard's landmasses gradually began to break up and decrease in size over the ages, though this would not be noticed by the general populace due to how gradual it was. However, over time the populace began to lose much more; Civilization thrives by building upon the knowledge of the past, and the disappearance of both Alchemy and seemingly Psynergy as well caused the various cultures of the world to lose knowledge and become more primitive over the ages. That is why in the current age when the Golden Sun games take place, Weyard is a fairly inactive and sparsely populated world, with scarcely few individuals being aware of the existence of the force of Psynergy, let alone possessing the ability to manipulate it as Adepts. A lot of the great Lighthouses, mountain sanctums, and other structures that stand today from the ancient past cannot be properly investigated by today's commonfolk because they lack the necessary adeptness to Psynergy that the locations were constructed in mind with.