Piety is one of the tertiary resources of your Civ. It is created by Clerics, who each require a temple building, or through a deity of the underworld. Piety is used in many upgrades in the game, as well as in creation of deities and deity upgrades.
There are two ways to gain piety. One is to purchase workers and assign them to a job as a cleric. The other is to make your deity one of the underworld and purchase the "Book of the Dead" upgrade which gives you piety with the death of your population, which is useful in conquest.
|Food • Wood • Stone – Skins • Herbs • Ore – Leather • Piety • Metal – Gold|