Its current era could be said to be the most prosperous era of the Empire, with five palace realm experts, of which those belonging to the royal family were four, but before that, in every era, there would be maybe one or two, with the number being mostly one palace realm expert.
Before the Red Maple Empire was established, the territory was under a different ownership and it was vastly different to what it was now. Back then it was under the rule of a tree spirit that had reached the peak of the palace realm, the tree which came as no surprise to Yang Qing when he read about it was a red maple.
That tree gained sentience and managed to cultivate to the peak of the palace realm. The majority of what is now the Imperial Capital of the Red Maple Empire and roughly 40,000 kilometers around counted as the territory of that Red Maple Spirit whose territory was much smaller than the present-day Red Maple Empire that had more than tripled in size.