Again, considering this as a bug, so it's here.
And have nothing to do with other topics about alliances.
I am in game, have 1 ally (not verbal one), my capital is taken.
We join our forces and retake my cap, still I am lost.
Don't you think, that there have be an option to pass Capitals (not all towns) to your Ally, or, consider this as "friendly forces retake your Capital, so you are not lose"
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Very vicious moderator