Once I could recite whole episodes of Dexter's Laboratory.
EMPIRE (B3) - The 10 public cards with a King (crown shape) on one side and a Republic (scroll shape) on the other. Each corresponds to a Map Card. Each empire starts in the empire stack (C5), but can be added to your Tableau by a Regime Change. If so, place it either in your furthest East or West position, or (during campaigns) as a Vassal.
Perhaps this is better placed in the Regime Change entry of the Glossary to keep moving of Empire Cards in one section. The Empire entry isn't really about moving Empire Cards about whereas the Regime Change is. It also already handles how Vassals are move to the furthest end when becoming a republic.