Celebrimbor was born in Aman during the Years of the Trees. Among Fëanor's seven sons, Celebrimbor's father Curufin was the chief inheritor of Fëanor's temperament and skills in craftsmanship.[2] In turn, Curufin passed these skills – but not this temper – on to Celebrimbor.[1]
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The whereabouts of Celebrimbor during the early years of the Second Age are uncertain. However, in S.A. 750, Celebrimbor with many others of the exiled Noldor established the realm of Eregion near to Khazad-dûm, the mansions of the Longbeard Dwarves. This they did due to the discovery of mithril in the surrounding mountains.
Eventually, a great friendship arose between the Elves of Eregion and the Dwarves of Khazad-dûm, such that was never before seen, and Celebrimbor became the Lord of Eregion and the greatest of the Gwaith-i-Mírdain, "People of the Jewel-smiths", who in their skill were second only to Fëanor, Celebrimbor's grandfather.
However, in S.A. 1200, Sauron, under the fair guise of Annatar, came to Eriador posing as an emissary of the Valar; and while rejected by Gil-galad, the High King of the Noldor, in Lindon (where he was not even admitted to), he was nonetheless accepted by the smiths of Eregion.
In c. S.A. 1500, the Gwaith-i-Mírdain reached the height of their skill under the instruction of Sauron and began forging the Rings of Power.