In 405 BC, Louis Jackaliv was the king of Atlantis, the forgotten city. One night, King Louis got a vision that Atlantis was to reach total annihilation. King Louis, desperate to save his people hired Rowen Quelross, a famed prophet to ask of what to do. Rowen was a very wise man and was capable of predicting the future. Rowen told the King to discard their old deity and to follow a different one, that was Fujibayashi Kyou-sama. But even though they worshipped Kyou as a God, they did not worship her fully hence Kyou-ism did not appear yet.
Exactly 30 years after, King Louis died from old age and passed on his position as the king to Itou Makoto , his adopted child. Itou Makoto had a bad reputation among the civilians and once he became King he banned Kyou-sama worshipping because he thought it was blasphemy. That was when disaster struck, the supporters of Kyou-sama raided the castle and defeated the King's men. One skilled captain, named Katsura Kotonoha cut off the King Makoto's head and brought him onto a very nice boat.
With Makoto out of the way, the Act of CLANNAD was passed which made Kyou-sama the official deity causing, Kyouism to be formed. During this time, the Kyouist spread word of the great Kyou-sama around the world. Unfortunately, the brief amount of time that the Atlanticans did not worship Kyou proved to be brutal. Soon, a young man named Rerouch Ramperouge and his wife C.C.C. came to Atlantis. Rerouch wanted to make Atlantis into her new-born daughter, Nunally's playpen. Rerouch encountered Takamachi Nanohako and used his divine power of Ceass to control her. Nanohako used her signature move, Sunlight breaker and obliterated Atlantis to the crisp.