Timeline

Post Transcriptum (Beyond 0)

↑ Year	Event
488	A bard sings the tale of Four Feathers.
444	Session 1 begins; Four Feathers forms.
441	Abador citizens endure mass petrification.
357	Discovery of the Realms.
29	Founding of the Scarlet Academy.
↑ Age of Discovery
0	The 100-Year War concludes victoriously.

Ante Transcriptum (Before 0)

↓ Year	Event
100	100-Year War commences.
↓ Age of the Wilderness
~400	Brassdorf is formed.
????	Myrneas is destroyed by Ozma.
????	Elves splinter and most migrate to Esuna.
????	Ozma is crowned king. Descends into madness.
????	A great asteroid hits the world in Istros Borealis, leaving behind the World Eater crater.

This is the complete timeline for Yggdrasil!

Age of Discovery

Directly following the 100-Year War, the largest ruling entities agreed to properly regulate the usage of magics. Powerful arch-mages around the civilised world banded together to catalogue and keep track of the various powers at large, forming the Scarlet Academy decades later to safely keep this information. Various other locations would also keep information and many governments would put forth laws regarding types of magics that were allowed to be used. While this is largely a collaborative effort to keep it regulated, not all types of magics were seen equal. Some parts of the world might consider Necromancy a forbidden magic, but others may consider some or all of that type be useful.

Elven knowledge

The Sylvan Realm has by far the largest knowledge base in the world. The long lifetime of the elven race allow them to better record or even witness notable historical events. That recorded knowledge is kept in their large cities, most notably Yls Dorei or in one of their many knowledge banks such as those in Aerthys. Sylvan Realm Recordkeepers remain vigilant protecting the many assorted libraries with vast knowledge, access to them is strictly forbidden and, for many non-Elven creatures, even punishable by law. A portion of records may be accessible what is deemed low importance, nonetheless access remains limited.

Age of Wilderness

The history before the 100-Year War remains largely unchecked as relics scattered throughout the world in hidden ruins or texts long forgotten in old libraries, abandoned or otherwise forgotten. The world populace was not as interconnected as today, information did not travel far as means of migration did not expand yet during this time. In addition to the lack of centralised recordings, many scriptures or other records from this era would also use varying forms of dating systems which would be making it difficult for modern researchers to put together a sequence of events as a coherent flow of that time.