I couldn't find any details on this so I can only assume it isn't implemented but that I'd like to see is some actual lineage and passing the Throne going on.

For example, once your Sovereign gets to a certain age he/she becomes a Figurehead only with city benefits until they die, and once they do the Throne passes to whoever is next in line. This should also be the case if you Sov falls in battle outside of your territory. As long as you have an Heir, you should be able to continue the game.

Thoughts?