According to dwarven accounts, why did the dragons declare peace?
Here's what the lore says, drawn directly from the indexed sources:
Dragon > Dragon > History It was not clear exactly how dragons came to inhabit Abeir-Toril, but many traditions believed their origin was related to the Tearfall. Some scholars believe this event precipitated a dramatic climatic change, which in turn sparked the rapid evolution of proto-dragons into the varied forms of dragonkind known today, while others claim that the dragon race was born from falling meteors that were actually dragon eggs. Regardless of their true origins, in the few centuries that followed their arrival to Abeir-Toril, the dragons generally kept aloof of the world's…
Source: Dragon
Vangerdahast Aeiulvana > Vangerdahast Aeiulvana > Retirement only the reigning monarchs and Elminster would know. When a song dragon named Ammaratha Cyndusk found out about the dragon-binding spell being made, she considered it too risky to allow anyone to develop the spell on the off chance that it was stolen and used to enslave the whole of the dragon race. She confronted Vangerdahast, who swiftly defeated her, but spared her life since he felt he had done too much killing in his life already. When a rogue War Wizard blasted Vangerdahast with a powerful spell, it momentarily shook…
Source: Vangerdahast Aeiulvana
Draconic pantheon > Draconic pantheon > History The draconic pantheon was one of the oldest pantheons of gods on Toril, having been worshiped by dragonkind since the creation of their race around. Dragons of that time were devout followers of their gods, and such devotion sparked intense wars, dubbed the Draco Holy Wars, over philosophical differences not only between different species but also within species. Over time, draconic philosophers came to the conclusion that all of the fighting was wasteful and that gods who allowed such behavior were not worthy of their worship. Some believed…
Source: Draconic pantheon
Annam All-Father > Annam All-Father > Creation of Ostoria After the birth of his terrestrial sons, Annam founded a kingdom called Ostoria for them and their offspring as a sign of his favor. He also established the ordning so that his mortal descendants could always know their status among each other. Dragons began to develop on Abeir-Toril some time after Ostoria's founding, and when the wyrms grew big enough, they began to compete and wage war with the giants for territory. Giant traditions held that Annam stopped the resulting Thousand Year War by convincing the dragon god Garyx to settle…
Source: Annam All-Father