When you control the maximum of five Altars in any given Kingdom instead of being able to Build a sixth Altar in that Kingdom, you may choose one of those Altars to Upgrade into a Temple - you can do this once per turn in each Kingdom in which you have any combination of five Altars and Temples. A Temple can pay one Devotion of any God or a (1). When a Kingdom has five Temples, there is no additional action that can be taken to Upgrade that Kingdom's Temples.