The Mithrim (S."Grey Host") or North-Elves were one of the three main tribes of the Sindar.They originally had been Eglath, Elves of the people of Elu Thingol, who had split from their main tribe and come to the northern Lands of Hithlum where they gave their tribal name to the region of Mithrim.They had been the first beleriandic Elves encountered by the Noldorin Exiles and the first Elves to be called Sindar. The Mithrim were and are Sindar, and share many beliefs, customs and motifs with their kinfolk the Iathrim, but being outside Melian’s Girdle in the First Age, they were usually left to their own devices. They were the first Eglain (Forsaken Elves, not the forsaken men in the Lone Lands) to encounter the Noldor, whose coming saved them from the Orcs that were in that year marching forth from Angband. Under the new Sun they swore brotherhood with the Exiles. This relationship persisted as the Noldor formed their kingdoms and into the dark days when Morgoth enslaved the North. As the wars raged, they fought under the banners of the sons of Finwe, practical considerations and increasing intermarriage estranging them from and including them in the isolation and mistrust that Thingol’s people developed for the Calaquendi.