Humanity, the way we know it, was created as a slave race to serve more advanced beings than their primitive human "creation". Humans in their DNA were programmed to be a submissive working force, not able to embrace their full consciousness with their DNA.
Since then, humanity has been living and evolving according to its level of consciousness through history.
With this low programming and limitations that came with humanity came an unbalanced reality into this world and humanity has needed help in its evolutionary process.
More advanced alien beings from the Universe know the Cosmic law of free will, which includes species and civilizations, and therefore are not allowed to intervene directly in humanity´s progress.
The problem is that the planet itself, Earth or Gaia, is suffering the consequences of such unbalance to an alarming degree which puts it on risk of destruction.
In the meanwhile, humanity has kept carelessly supporting the same self destructive system for ages and ages, sometimes un-aware of the destruction they/we cause... Other times, simply indifferent to it. The root is the same though: Lack of connection.
Anyways... So, the planet does not want to be destroyed in the process. She wants to evolve and more on to the next reality. However, she´s on the path towards its own destruction (not anymore). Some advanced souls decide to help the planet and its beings. Since they cannot directly get involved, what they can do, is to incarnate inside a human reality and make the "work" from there.
This comes with a cost: The cost is to temporarily lose their full consciousness during their incarnation process. This means: They forget who they are and why they are here. All they can feel or remember, is being worthy and coming here for doing big things.
The challenges that this purpose brings are so big, that only very courageous and advanced souls decide to take the risk and to fulfill their purpose, whichever it may be.
There is the belief that these advanced souls who have incarnated into humans and have done great and meaningful things to help human evolution, are the great personalities of our history. The ones who are still remembered today because they stood out because of their achievements and the value they left to the world. Also, because they took active part in historical events and are the ones who shaped and continue to shape history and to trigger evolution.
Most of these souls are the same group of souls incarnating again and again, playing several important roles, taking on the challenges and leaving their message and gifts to the world. In the process, these souls gather a lot of karmic baggage through their lives. Some of these souls are wise and broken in their current life.
However, they know their inner worth; or at least have the intuition of who they are and what they are capable of, even with all the baggage and brokenness. They know they are here for something big because they know that this is already who they are, so they dont usually give or express less than who they are in their life.
Artists, musicians, scientists, politicians, public figures of different kind, spiritual figures, mystics, philosophers, inventors, thinkers, entrepreneurs, activists and even military and royal figures... They have played roles, not always considered positive ones, but life-changing, meaningful and important for humanity´s growth.
Now more than ever, during these important times we are living in, the times of awakening and ascension, many of these souls are incarnated right now either doing their part or preparing themselves for what they came here to do. For "leading" this ascension process and helping humanity with it.
This is a theory which I have seen on different times and also told to me by few random people. It is out there, not sure if this is true or not but any insight on this is welcome.