As per my beloved in-laws, the letter told a story of how one of the high ranking priests of the church met someone who is most likely the reincarnation of the goddess that established their religion, Lumienere. They believe that she is the goddess of creation and life. The pope mentioned that there was a prophecy that the goddess will descend to Aeocrescens once more when the right time comes to bless all beings.
The letter then indicated that the person who met the goddess was someone directly connected to the Pope, to be specific his very own grandson so his report was very credible. His grandson specifically said that he met the goddess in Rigden who went there as a royal envoy. This high priest then asked help directly to the pope and the council of high priests to help him find more information about the woman.