Church Shrine I is built in the Church for 4 Wooden Plank, 6 Bronze Nails and 3 Piece of stone. +2 church quality. Unlocked by Church Furniture I. Its construction site needs Building mastery 2: below that, hits do nothing.
It adds 2 to church quality. More elaborate sermons need a higher church quality. Each new best church quality counts towards the Sacred Interior inspiration. Church Furniture I also unlocks Confession Booth I.