Pony histories been exisiting since first civilizations, we humans been consider ponies as gods, in the Ancient Egypt the scultures and works are about ponies, all Gods of the sun (Huitzilopochtli,Horus, Apollo, etc.) are replaced by variants of Celestia through time and same as Luna with the moon and Twilight with the Wisdom, there always been books about Twilight and the mane 6 as semi goddess, while the rest as Angels and symbols
all the paintings of Michelangelo di Lodovico are replaced by drawings of ponies and the sculpts are a variated way between pony and anthro.
there was no holy war, we learned to love and tolerate this time, humans split into 6 tribes: pegasus people, crystal, alicorns, unicorns, changelings and earth ponies, each ones with their own rules and manners, each tribe has a leader or president, and they go to some islands named Canterlot as a equivalent of the United Nations, all the leaders help each other and make an aliance.
there been persons through time that talk about a heaven named Equestria that is the same of the show, people become ponies and live like the show. there are books about the ponies and humans pray to Celestia, Luna and the mane 6, weddings, funerals, baptism are made in pony influence, in this modern age humans made reseach to find the heavenly gen, the one that make us ponies and there's also some experiments with humans to make them ponies, the research about the unicorn magic is also very popular in the scientist matter.
real ponies are worshipped and those are seen as a link between this world and the equestrian heaven.
when humans get the majority of age they receive a tattoo of two symbols: one about the tribe they belong (unicorn, pegasus etc) and the Cutie Mark, is a symbol of the abilities of the person but that last one is apply when the person is sure of his skills, and is better for job oportunities.
now i ask, you think is a good place? feel free to comment