How do spies cause rebellions?

[Tough Guy]

I either drop them on a general to reveal vices or on a territory to do "spying".

I've seen posts about spies causing rebellions. How is this done?

Also, I've heard that spied can tell of an impending invasion. How is this done? Is it by leaving a spy in an enemy territory(as opposed to dropping him on a general)?

Tough Guy

[chunkynut]

They decrease loyalty to a faction in a teritory when in that faction teritory. When you have many spies in that teritory the loyalty drops considerably and you have your rebellion. http://www.totalwar.org/ubb/smile.gif

[Redllama]

In the game I'm playing I was building up spies, trying to start a few rebellions, and generally taking over the world. As the Almohad I was allied with 5 different factions. In one turn, I was attacked by the Turks, the Polish, the Novogdrad and the HRE. They had all been allies the turn before. So after 8 hours of battles I finally get to the real part of my turn, and up pops a message from my spy saying he thinks maybe the polish are planning an attack. http://www.totalwar.org/ubb/frown.gif A little late.. Coulda used that information a little earlier.. but he was a low valor spy, maybe better ones will get the info to you on time. So they do have cool stuff to tell you.