On the day of the Summer Sun Ceremony, the Divine Radiance sent forth to the town of Ponyville her beloved and Faithful Disciple, who with the Blessed Hatchling of Light were to proclaim the word of the Sun and prepare the way for the coming of the Divine Radiance and the miracle of the Rising of the Sun the next morn.

But dark forces lay in wait for the Faithful, and many were the trials she was to endure before her task would be complete.

Editors: Bad Horse, Tek, and Various Divine Beings Who Shall Remain Nameless
Cover Art - Pope Celestia by Kippzu, I think.