How far back could the levels in cultivation novels such as Nascent Soul and Golden Egg go?

In the setting of cultivation novels, Nascent Soul, golden eggs, and other high-level existences usually represented that the cultivator's strength had reached an extremely high level. However, there was no definite answer to the origin of these levels and where they could be traced back to. In some novels, the appearance of the Nascent Soul realm and the golden egg realm might be achieved through some special means or experiences after the cultivator reached a certain realm. However, there were also some early cultivation settings in these novels. In some early cultivation novels, it was possible for cultivators to gradually reach the level of Nascent Soul or Golden Egg through cultivation, enlightenment, and other methods. These settings could be traced back to the early martial arts novels. In the martial arts novels, some cultivators could finally reach a realm similar to the Yuanying realm or the golden egg realm through continuous cultivation and enlightenment. There was no definite answer as to where the levels in cultivation novels such as the Nascent Soul realm and the Golden Egg realm could be traced back to. It might involve different authors, works, and cultivation settings.