While still in his early youth [Fëanor] wedded Nedanel, the daughter of a great smith named Mahtan, among those of the Noldor most dear to Aulë….Nerdanel also was firm of will, but more patient than Fëanor, desiring to understand minds rather than to master them, and at first she restrained him when the fire of his heart grew too hot; but his later deeds grieved her, and they became enstranged. Seven sons she bore to Fëanor; her mood she bequeathed in part to some of them, but not to all.
—J.R.R. Tolkien, The Silmarillion, ch. 6: “Of Fëanor and the Unchaining of Melkor”