[1] It explores the etymology of the Old English word for the ancient Aethiopians, Sigelhearwan, and attempts to recover what it might originally have meant.
The Tolkien scholar and philologist Tom Shippey suggests that Tolkien's detailed study of the word may have influenced him in his creation of elements of his fantasy world of Middle-earth, including the Silmarils or forged sun-jewels, the Balrogs or dark fire-demons, and the Haradrim, men of the hot south.
He begins by pointing out that Ethiopians in the earliest writings are presented in a very positive light, but by the time they written of as "Sigelwarans", the perception has become the opposite.
Suggesting a connection of hearwa with Gothic 𐌷𐌰𐌿𐍂𐌹 hauri "coal", Old Norse hyr-r "fire", Old English heorþ "to roast", heorð "hearth", Tolkien tentatively concludes that in the Sigelhearwan we may be looking at "rather the sons of Muspell than of Ham", an ancient class of demons "with red-hot eyes that emitted sparks and faces black as soot", English equivalent of the Norse fire giants ruled by Surtr, that had been forgotten even before the composition of this version of Exodus.
Tom Shippey notes that the demons "with red-hot eyes" make appearances in Tolkien's fiction as Balrogs.