Re-emerging factions

[Calypze]

I am playing a Romani campaign, where I control all of the Italian peninsula as well as the three originally Celtic provinces right beneath the Alps, Massalia , southern Gaul (slowly working my way up) all of Iberia, all of north-western Africa, plus of course Sicily, Corsica , and the Balearic Islands.

The Massalians re-emerged in western Africa years or decades after I had defeated them. I am now playing a whack-a-mole with them in the desert. I have severely reduced the size of their stacks. If I let them live, will their stacks eventually grow in size, or will they remain at the same size? if I destroy them, could they re-emerge again?

Also, what can you do to decrease the probability of factions re-emerging? It would be really tiresome if the Iberian factions re-emerged, for example.

[QuintusSertorius]

Faction re-emergence and horde respawns are forever, you can never permanently end them. This is by design to ensure no faction can ever truly die.

Faction re-emergence is triggered by unrest in their historical capital. Keep that pacified and re-emergence won't happen.

Hordes re-appear randomly after they are destroyed, there's nothing you can do to influence that.

[Airos]

Reduce them to a very poor landlocked province and make them a vassal.

This should keep them at bay : no expansion, no war, no revolt.

That's pretty much what the roman did historically anyway.

[Calypze]

I drove the Massalians to Egypt, where they attacked the Ptolemaioi, who had been my ally for about a century, but was about to backstab me. (I mean, if they bring ships loaded with troops heading toward lightly garrisoned Carthago, what could possibly be their intention? I sank their ship before finding out.) They took a province there, so I made pace with them and later allied with them. They can certainly serve a useful purpose for the Roman Republic by undermining its enemies.

[Aethis]

I usually just pack them off to Gaetulia and Phasania.