Tomás de iriarte (1750-91) is often called upon to furnish early or embryonic examples of modern metric forms because he, perhaps more than any other writer of his time, consciously attempted to exploit the wealth of Spanish verse and strophe arrangements then known and to enrich the language with new forms and combinations. Emiliano Díez Echarri even goes so far as to say that Iriarte was “capaz con un poco más de estro poético de haber renovado toda nuestra métrica.” Other well-known scholars, including Menéndez y Pelayo, Miguel Antonio Caro, Manuel González Prada, Julio Saavedra Molina, Pedro Henríquez Ureña, and Marasso Roca, to name only a few, have at one time or another studied some phase of Iriarte's versification, though no general survey of it has, to my knowledge, been made. The “Géneros de metro usados en estas fábulas” appended to the Fábulas literarias lists forty types, but does not tell the whole story of the versification in the Fábulas—much less of Iriarte's work as a whole. A study of Iriarte's versification would have at least a threefold value: it might (1) serve as a near equivalent to a summary of Spanish formal or learned versification to and including his time; (2) indicate a stronger Italian influence on Spanish metrics at this particular period than has generally been suspected; and (3) bring into clearer focus the original or near-original phases that may have influenced subsequent metric technique, given the fact that Iriarte's work has been so widely known. This paper will attempt to expand especially the first and third of these features of Iriarte's work.