Church Shrine III is built in the Church for 1 Paint, 3 Advanced Detail and 3 Polished Marble. +6 church quality. Unlocked by Church Furniture III. Its construction site needs Building mastery 4: below that, hits do nothing.
It adds 6 to church quality. More elaborate sermons need a higher church quality. Each new best church quality counts towards the Sacred Interior inspiration. Church Furniture III also unlocks Confession Booth III and Church Smells III.