War of the Dwarves and Dragons

The War of the Dwarves and Dragons was a conflict that took place from TA 2570 to TA 2589.

Background
The defeat of Morgoth in the War of Wrath left the Dragons few and weak, hiding in the Forodwaith of Middle-earth. But over the millennia the Dragons multiplied and became strong once again. Even centuries before the beginning of the war, the Dragon Scatha had stolen treasure from the Dwarves and kept it in his hoard; unfortunately, Scatha was slain by Fram of the Éothéod, who kept the treasure for himself.

History
In TA 2570, the Dragons made war on the Dwarves of the Grey Mountains in the Ered Mithrin, sacking and plundering their halls and mines. The war lasted for almost twenty years, but in TA 2589 the Dragons attacked the halls of King Dáin I, and outside city a great Cold-drake killed the king and his second son Frór.

After this defeat, most of Durin's folk abandoned the Grey Mountains. King Thrór and some of his followers went back to the former Dwarven dwelling of Erebor, while his younger brother Grór led others to the Iron Hills.

Aftermath
The Dwarves of the Iron Hills, as well as the Dwarves of Erebor, managed to prosper for the following couple of centuries. However the threat of Dragons would revisit their history: in TA 2770, Smaug flew south from the North "like a hurricane" and attacked the wealthy Dwarven Kingdom.