From Civ World
Ministries are very high ranks in a civilization. They share power with the King and help each other lead the civilization. Each minister gains a special ability unique to their role that they can use to boost the civilization in a specific way.
Becoming a Minister
The Defense Minister can give Battle Orders to other players' armies, in addition to their own.
The Political Minister can veto a vote unless it's 2:1 in favor.
The Interior Minister gifts one Harvest to a random player in their Civilization each time they complete a Harvest.