Gwaith-i-Mírdain

The Gwaith-i-Mírdain was a brotherhood formed by Celebrimbor and the other master craftsmen of Eregion in the Second Age. They were said to be the most talented artisans to have worked since the time of Fëanor himself (who was Celebrimbor's grandfather). Their skill was subverted by Sauron, in the guise of Annatar the "Lord of Gifts", who focused their abilities on forging the Rings of Power.

Gwaith-i-Mírdain means "Brotherhood of Jewel-smiths" in Sindarin (from gwaith = "host, brotherhood" and mírdain = "jewel-smiths").