Injury
One after another, the representing envoys of each country stepped up to the treaty, signing it. While they were signing it with their personal signature, they were here to represent their respective countries. As such, the peace treaty was a contract effectively signed between each of the different countries in question.
Once a signature was placed, it would fade, and their country's sigil took its place. And then, finally at the end, all of the sigils of the signing countries were represented.