The Seven Hoards of the Dwarf-kings were legendary treasures of the Dwarves. The name suggests that each hoard belonged to one of the seven Dwarven clans. As it is said, the foundation of each hoard was a golden ring, and they were probably gathered thanks to the Seven Rings given to the Dwarves by Sauron in the Second Age.
By the Third Age, the hoards had been plundered and devoured by Dragons.[1]
Smaug had once claimed a dwarven-hoard, but it is not known if it was one of the Seven Hoards.
See also