During the later thirteenth and early fourteenth centuries, Giles of Rome, one of the most outstanding thinkers played the important part in respect to the controversy about the real distinction between "esse" and "essentia". He wrote two books about htis problem; "Theoremata de esse et essentia" and "Quaestiones disputate de esse et essentia." E. Hocedez maintained that Giles physically and materially interpreted the problem of the real distinction in Thomas Aquinas, indicating the neoplatonic characteristics in the doctrine of the real distinction in Giles of Rome. The novelty in Giles' thoughts on the real distinction pointed out by Hocedez is as follows; (1)"esse" and "essentia" are two things. (2) "esse" can be separated from "essentia". (3) the systematical use of "forma totius" and "forma partis" for the purpose of explaining the formula "forma dat esse". In this article, I intend to show that Hocedez' interpretation concerning "Theoremata" is historically not legitimate; Giles was a Thomist in the sense that he overcame the Essentialism and that he rightly understood the metaphysical, transcendental character of "esse", asserting that "esse" does mean the foundation of being as an act, not "existere in rerum natura".