My theory like other has flaws but I am really trying to wrap my head around what we've understood throughout the show. My idea and feel free to rebut it is that at the beginning of time about 6,000 BC, a superior being (god, gods, alien, spirit etc.) created the Neolithic culture rooted in Egypt within the Nile valley. Egyptian societies started flourishing, forms of writings (hieroglyphs) appeared around 3,500 BC and a kingdom was forged in 3,150 BC by King Menes; Egyptian people referred to the dynasty as 2 worlds "tawy" - The first world "earth" had been created to let civilizations normally evolve throughout time while the second world had been created as a sanctuary, a place of magical and extraordinary properties. The island was meant to be secret and hidden from earth in a different temporal zone.
This sanctuary served as balancing the earth and self-correcting everything. The superior being sent Jacob a ! human worthy of divine "empowerment" to the Island to watch civilization unfold and ensure that balance would always be ensured in the world. Jacob would be granted eternal life and allowed to intervene to resolve conflicts in the world by going off island and trying to convince perpetrators of conflicts and wars to change their course of action. Jacob could only influence people to change through free will and certain logic. He failed many times, the kingdom of Egypt went through many wars, instability and terror developed on earth...From the Island Jacob who could be in direct contact with the superior being implored "it" for help - The superior being agreed to rid the earth of evil which unfortunately had been created by the imperfection nature of human beings - evil would be expunged from each human on earth and brought to the island into the form of black smoke - this black smoke, this aggregation of evil spirits, thought etc. would be condemned to the island in the fo! rm of a "human being" the MIB. The superior being warned Jacob! that this measure might be temporary as the world could fall back into evilness and that he would have from now on to bring people to the island over and over to have them confront pure evil on the island & prove their worthiness by not falling into the temptations from "evil": greed, power, success, lies etc. Rules had been set that way...Now we can figure out the rest from the show with Egyptians coming to the Island building tawaret,the black rock, dharma teams etc. etc. Jacob being incapable to redeem anyone and being give one last chance by finding candidates who can actually accomplish this mission otherwise the evil spirit might be evil to leave the island, return to earth and create chaos..
I am sure I am missing a ton of things but was trying to think of how the island came to existence. Thoughts?