But to understand was not enough for Schiller; there were in him faculties which this could not employ, and therefore could not satisfy. The primary vocation of his nature was poetry: the acquisitions of his other faculties served but as the materials for his poetic faculty to act upon, and seemed imperfect till they had been sublimated into the pure and perfect forms of beauty, which it is the business of this to elicit from them. New thoughts gave birth to new feelings: and both of these he was now called upon to body forth, to represent by visible types, to animate and adorn with the magic of creative genius. The first youthful blaze of poetic ardour had long since passed away; but this large increase of knowledge awakened it anew, refined by years and experience into a steadier and clearer flame. Vague shadows of unaccomplished excellence, gleams of ideal beauty, were now hovering fitfully across his mind: he longed to turn them into shape, and give them a local habitation and a name. Criticism, likewise, had exalted his notions of art: the modern writers on subjects of taste, Aristotle, the ancient poets, he had lately studied; he had carefully endeavoured to extract the truth from each, and to amalgamate their principles with his own; in choosing, he was now more difficult to satisfy. Minor poems had all along been partly occupying his attention; but they yielded no space for the intensity of his impulses, and the magnificent ideas that were rising in his fancy. Conscious of his strength, he dreaded not engaging with the highest species of his art: the perusal of the Greek tragedians had given rise to some late translations;[29] the perusal of Homer seems now to have suggested the idea of an epic poem. The hero whom he first contemplated was Gustavus Adolphus; he afterwards changed to Frederick the Great of Prussia. [Footnote 29: These were a fine version, of Euripides' _Iphigenia in Aulide_, and a few scenes of his _Phœnissæ_.] Epic poems, since the time of the _Epigoniad_, and _Leonidas_, and especially since that of some more recent attempts, have with us become a mighty dull affair. That Schiller aimed at something infinitely higher than these faint and superannuated imitations, far higher than even Klopstock has attained, will appear by the following extract from one of his letters: