What happens if the foreign realm with whom you want to sign a treaty does not have an ambassador?
Talk to their Ruler.
Which means either:
1. Ask the ruler to sign it himself.
2. Ask the ruler to appoint an ambassador to sign it.
Either way works.
And how does an ambassador propose a signed treaty to a foreign realm>? Must he travel to their capital or something?
Also taking my steps to become an ambassador myself. Start to discover this new class of BM myself as well. It's helpful as ruler if you know how it works.
Be in any region owned by target realm for treaty. Declarations need only be signed by your realm's ruler or any ambassador of your realm.
Rep +
Thanks, that helps a lot. We have some treaties we want to propose to our allies and neighbours.