The event that marked the beginning of Gliea as it is known today. The turning point in whole history.
In 0 AD, the gods of the Creed of The Seven descended down to Gliea and gave races the gift of magic. By doing so, these races gained access to knowledge that they couldn't event imagine before and their growth was not unrestricted. This in turn lead to a great advancement in all the fields.
After the end of the Age of Descent settlements and tribes turned into kingdoms and empires.
It is believed that for three years gods have walked Gliea before ascending back to their realm.
Before leaving, the gods left 7 books behind - that were the foundation of the Creed.
Since that time, first record of Tieflings and Dragonborn were noted.