of the one and only true God, Maleldil. As noted by Lewis in the non-fiction book The Discarded Image, the identification of the Greco-Roman gods as angels can be traced to late medieval and Renaissance times, when European intellectuals rediscovered and highly valued works of classical antiquity where references to these gods abound, and this needed to be reconciled with these intellectuals' Christian faith. Hnau Hnau is a word in the Old Solar language which refers to "rational animals" such as humans. In the book, the Old Solar speaker specifies that God is not hnau, and is unsure whether eldila can be termed "hnau", deciding that if they are hnau, they are a different kind of hnau than humans or Martians. The term was adopted by some others, including Lewis's friend J. R. R. Tolkien; Tolkien used the term in The Notion Club Papers, which were not published in his lifetime. Tolkien distinguished hnau from beings of pure spirit or spirits able to assume a body (which is not essential to their nature). Similarly, a character in James Blish's science fiction novel A Case of Conscience wonders whether a particular alien is a hnau, which he defines as having "a rational soul". The term has been used by philosopher Thomas I. White in "Is a Dolphin a Person?" White asks if dolphins are persons, and if they are, whether they can also be reckoned as hnau. Old Solar language According to the Space Trilogy's cosmology, the language of all the inhabitants of the Field of Arbol is Old Solar, or Hlab-Eribol-ef-Cordi. Only Earth lost the language; this loss was due to the Bent One's influence. Old Solar can be likened to the Elvish languages invented by Lewis's friend, Tolkien. The grammar is little known, except for the plurals of nouns. The plurals of some words (hross, eldil) are simple, only adding a final -a or -i; others (as for Oyarsa, sorn, hnakra), are quite complex broken plurals, adding an internal -é-, and adding or altering a final vowel (usually to -i or -u), and may also include internal metathesis (Oyéresu, séroni, hnéraki). Old Solar is also referred to as "the Great Tongue": Terms used throughout the trilogy Eldil (pl. Eldila): An everlasting, rational, "multidimensional energy being" that is not organic; an angel. Some act in the capacity of "Oyarsa" of a planet. Field of Arbol: The Solar System. Glund or