Due to the adventure with the Time Key, Shard learned that during the Fifth Era, there were at least five continents known as "East, West, South, North, and Center," along with numerous islands like the "Shattered Isles" overseas. This can also be confirmed from other available documents.
As for why there are only the Old Continent and the newly discovered New World in the Sixth Era, the views in the Circle Sorcerer academic circle vary. But it can be determined that the current "Old Continent" shares the most commonalities with the "Midland" of the Fifth Era, although it also exhibits features from other regions.
If we use "space" folding to explain this phenomenon, it becomes clear.
"World folding... Will there be omens of the overlap between North and South cities of Green Lake?"
