All I know about diplomacy is that both the HRE and Milan are dirty backstabbing liars. (They both broke their alliances with me and then made an alliance between themselves in 2 turns, and they did this in TWO consecutive campaigns!)

The OP indicated that they might be more willing to agree to a ceasfire if you have a massive army marching through their lands. Is this true? I would actually like to NOT have my entire eastern boarders embroiled in a war, but neither country will listen to reason. Would sending a massive army into their territories change their minds?