Slitherine

In an alliance you can be drawn into an unwanted war if your ally declares war. Would the option of a defence pact instead, where you only declare war if your ally is attacked, be non-historical? The earliest formal one that I can find is in the 14th century, but surely they could have been negotiated earlier than that. It would be a nice addition to the game.

Well, it depends on the relation you have with your ally. Below 50 points, it's indeed a purely defensive pact, you won't be drawn into the wars declared by the ally; starting 50 points, it becomes a full alliance in which the AI has the bad habit of plunging you into countless meaningless wars. Breaking them down into two different pacts (defensive alliance & full alliance) would make for a QoL improvement though!

You can insult your ally's emissary to keep them below 50 relation; personally I only resort to cooperation agreements since it's less of a chore to manage (cooperation can effectively bring you above 50 relation to prevent the target from declaring war on you). Only the start of turn messages about an alliance request need to be dismissed in this case, however that also prevents you from making any transactions should you want to (the diplomatical display is limited to accepting or rejecting the request).

defiendo totalmente el pacto sagrado