Possible Clues:

• Tycoons' holdings
• See about the prim mixture of possessions
• 'E's past the prime of such possessions
• Being in such possessions is all the rage in Parliament
• That would seem to be just about the RIP of possessions
• Groups of states under one sovereign
• Domains ruled by an emperors
• Aztec and Inca, e.g
• They rise and fall periodically
• 'I'm in colonies, along with my peers (7)'