Message: "Your Faction has been eliminated"

[HindSight2020]

I've been playing a single player campaign for a while now. I made it to A.D. 10 (or there-abouts). Suddenly, I received the message (in rather large lettering), "Your faction has been eliminated. Do you want to continue playing?" I chose to continue playing. I didn't notice any change. I am still rated by the Senate and the people as being ahead of the other two Roman factions, and I'm still getting instructions from the Senate on missions and tasks to complete. So I'm puzzled about the message. I was wondering if anyone else had received this message and whether anyone knew what it meant. (Sorry if this is an old issue and if it has already been covered.) Is there a limit of years in which you have to attack Rome and take on the other two Roman factions? Or is something else going on?