The Treaty of Lavos was, to date, the only treaty that ever ended a war at a Dealing, the Dealing of 310 AC, ending the War of Woods between the Zaentovi and the Ethrykian Alliance, which consisted of Ethryke, Ceryne, Lavos, and the Kingdom of Andoras, after nearly eighteen years of constant conflict. Alongside this, the treaty also established the Drakonian Union, which still remains as a coalition-based alliance against any would-be attackers of the Edrossian nations.
The Zaentovi had been fighting the Ethrykian Alliance on all fronts of the Leyse Woodlands, clearly intent to keep what they believed what was theirs. The citizens of Ethryke began to starve during a famine, and knew that the Woodlands to the north had food and fertile land. The War of Woods of 293 AC arrived, it and it did not end until 310 AC. After those 17 years of fighting, the Zaentovi were finally driven back from the woodlands, returning north to the Wailing Wilds, and beyond that, the Zaentovi Wild. Some continued fighting, not acknowledging the peace summit that the Dealing served as.
The Treaty of Lavos, proposed a few weeks before the Dealing of 310 AC and made one of the priorities to be discussed at the Dealing, was due to be signed by both the Zaentovi and the members of the Ethrykian Alliance. The Ethrykian Alliance agreed to consider the war to end in a tentative white peace; to declare that no one truly won, even though the Alliance, in reality, won a narrow victory; Ethryke recovered its land that it lost 80 years prior and the Zaentovi lost thousands of their men to a campaign that ended up to be a failure for them. The Alliance was not without its losses, but the victory was still had.
For this reason, the Zaentovi lost a lot of their external national pride, something they valued greatly, and attempted to delay signing the Treaty until it was absolutely necessary. When the Zaentovi ambassadors were asked to come to the Hall of Pryiore in the center of the Villa, they did not reply and were found in a guest bedroom hiding their heads in shame.
The new-age Zaentovi acknowledged the peace treaty and stood down, but the old-age Zaentovi did not leave the Woodlands until 317 AC. This would mean that the fighting directly related to the War of Woods' original purpose lasted for seven years after the Treaty was signed, and 24 years altogether. The Zaentovi also plotted to ambush and siege the city of Ethryke while the Dealing was proceeding, planning to remain under a state of war to defend the Woodlands, and once this was discovered after the treaty was eventually was signed, were banned from any future Dealings unless specifically invited to them. They have only attended the Dealing of 345 AC since, in a delegation related directly to the War of Woods. They had not truly amended relations until nearly half a century after the war ended.
Inspiration for possible other treaties
While the War of Woods is so far the only war to be ended through one of the Dealings, there have been other opportunities for wars to be ended, but cooperation was not earned or intervention was deemed unnecessary.
Examples of wars that may have ended prematurely if they had been ended at a Dealing:
The 326 AC rebellion, the Farmers' Revolution of Andoras. It began merely a month after the Dealing of 325 AC, and was still being fought when the Dealing of 330 AC was held. The 330 AC Dealing was particularly noted for being the only Dealing that the Farrowhalt Freehold as a nation had attended, despite that the Six-Day-Siege had already occurred, any remaining splinter of Freeholder territory was captured three days prior to the Dealing's beginning, and that Veddel Markwell and Michael Avleston were still technically in hiding. Peacekeepers did not allow bringing any conflict to the halls of Pryiore Villa, and so they remained safe for the time being. Both parties and their leaders were present, and Veddel Markwell, being the head of state, argued in favor of ending the war as a 'bloody pyrrhic victory for the Freehold.'
Aegor IV Dragomyr vehemently fought for his own stance, that the Kingdom of Andoras was rightful in defending itself from rebellion. A verdict could not be reached between either party, and the idea of a treaty, presented by overseer Naimen Dolore, was turned down by both parties.