The basic grammatical study of the period, based upon the _shōmono_ materials, is Yuzawa Kōkichirō, _Muromachi jidai gengo no kenkyū_ {27} (Tokyo, 1958). More closely related to the language reflected in the text is his "Amakusabon Heike monogatari no gohō," in _Kyōiku ronbunshū_ (no. 539, Jan. 1929). An English treatment of the grammatical system of the period is to be found in R. L. Spear, "A Grammatical Study of _Esopo no Fabulas_," an unpublished doctoral thesis (Michigan, 1966). The phonology has been carefully analyzed by Ōtomo Shin'ichi, _Muromachi jidai no kokugo onsei no kenkyū_ (Tokyo, 1963), with a valuable contribution made in English by J. F. Moran, "A Commentary on the _Arte Breve da Lingoa Iapao_ of João Rodriguez, S.J., with Particular Reference to Pronunciation," an unpublished doctoral thesis (Oxford, 1971). This latter work presents an exhaustive examination of the phonological system reflected in the _Arte Breve_ of 1620 within the framework of Berhard Bloch's phonemic theory. Two lexical works have been used as basic references in this translation. The _Vocabulario de Lingoa de Iapam_ (hereafter the _Vocabulario_) produced by the Jesuit Mission Press at Nagasaki in the years 1603 and 04. In a carefully annotated version by Professor Doi, under the title _Nippo jisho_ (Tokyo, 1960), this work is the most important single source for the vocabulary of the period. The second work is the _Dictionarium sive Thesauri Linguae Iaponicae Compendium_ (hereafter the _Dictionarium_) which is the companion piece to the present text. This dictionary has been carefully edited and cross-referenced by Ōtsuka Mitsunobu, under the title _Koriyaado Ra Su Nichi jiten_ (Tokyo, 1966). In this form it has served as a constant aid to the translator in the determination of the proper glosses for the lexical items in the text. The aforementioned _Arte_ of 1604-08 by Rodriguez, has been the single most frequently used tool in the preparation of this translation.[40] As the most significant influence upon Collado's work and the source for most of his material, both theoretical and practical, I have related the two works at every point in the translation. In its Japanese version by Professor Doi, _Rodorigesu Nihon daibunten_ (Tokyo, 1950), this work has been invaluable in gaining a clearer understanding of many of the passages which might have otherwise been obscure. Rodriguez' _Arte Breve_ of 1620, while having no influence upon the preparation of the _Ars Grammaticae_, is nevertheless of fundamental {28} importance as a work against which Collado's treatment of Japanese grammar is to be judged. This shorter grammar is as yet to be fully translated into English--Moran having limited his study to the treatment of the phonology.