The people of Aradan (for Marach his father remained in Estolad until his death) for the most part went on westward; and some came to Hithlum; but Magor son of Aradan and many of the people passed down Sirion into Beleriand and dwelt a while in the vales of the southern slopes of Ered Wethrin. ~ The Silmarillion, Chapter 17 (House of Hador by enanoakd, deviantART)