. . . and THIS is the thanks I get??

[Prussian1]

I have been playing MTW for several years, but this is really the first time this has come across my plate.

I had an ally who was invaded by a relatively small army in an adjacent province, who was forced to retreat to his fortress.

I figured "What are friends for" and sent in an Army to lift the seige.

This was considered an act of war by my ally.

Ouch . . . .

I have yet to figure out why alliances were put into the game in the first place, as there seems to be no benefit or penalties involved in making or breaking them.

[Ciaran]

There is a penalty for breaking an alliance, your King will suffer a significant loss of influence.

And by all rights, in the situation you described it shouldn´t have been a breaking of an alliance, unless your common enemy had retreated his forces before your attempt to liberate your ally.

It should teach you something about helping allies, though

[Martok]

Yeah, you actually should've received an influence boost for relieving the siege. As Ciaran said, the only thing I can think of is if the other faction retreated from that province in the same turn you moved in to help out your ally.

And breaking an alliance does cost your faction leader influence.

[Prussian1]

And breaking an alliance does cost your faction leader influence.

Hmm . . . that could be why the Italians, who have a long history of breaking alliance with me and attacking (and getting stopped cold at the Tyrolian Border by the HRE's finest) will almost always be thrust into civil war.

[Martok]

Hmm . . . that could be why the Italians, who have a long history of breaking alliance with me and attacking (and getting stopped cold at the Tyrolian Border by the HRE's finest) will almost always be thrust into civil war.

That's very possible, yes. If a faction leader loses enough influence -- whether through breaking alliances, losing territory, a failed Crusade/Jihad, or any combination thereof -- in a short enough period of time, it's entirely likely that his faction will in fact plunge in to mass rebellions and/or civil war.

[caravel]

I'm sure that if they retreat the same turn that your army is still there you are to be considered as having lifted the siege. The only explanation for this is that they were not your ally. They may have allied with one of your enemies that every turn which is what would have broken the alliance.