Port Royale 3

This needs to be done at the church. Every port has a church so all you need to do is make sure your ship is docked or you have a building in town. Highlight the church and you will see an option to pray. Do this 10 times and the achievement is yours. 

NOTE: Although this can be done all at once in the same church, you won’t be able to spam  10 times in a row. You need to wait until the hymn/chant sound in the background finishes each time.