YouTuber The Middle Man explains the religion of Mithraism as fictionalized in the TV series Raised by Wolves.
In the series, a reconstruction or revival of the ancient Roman mystery cult of Mithraism quickly gains religious (and then political and military) hegemony during the 22nd century, due largely to its use of a new technology that is attributed (within the cult itself) to encoded writings dating back to the pre-Christian era. However, the Mithraic war with the Atheists brings Earth to the edge of total ecological ruin, sparking the interstellar ark mission that forms the background of the Raised by Wolves story.