Fremere intanto udia continuo il vento
    Tra le frondi del bosco e tra i virgulti,
    E trarne un suon che flebile concento
    Par d’umani sospiri e di singulti;
    E un non so che confuso instilla al core
    Di pieta, di spavento e di dolore (xiii. 40).

The master word, the magic word of Tasso’s sentiment, is uttered at this moment of illusion.  The poet has no key to mysteries locked up within the human breast more powerful than this indefinite un non so che.

Enough has been said to show how Tasso used the potent spell of vagueness, when he found himself in front of supreme situations.  This is in truth the secret of his mastery over sentiment, the spell whereby he brings nature and night, the immense solitudes of deserts, the darkness of forests, the wailings of the winds and the plangent litanies of sea-waves into accord with overstrained humanity.  It was a great discovery; by right of it Tasso proved himself the poet of the coming age.

When the Gerusalemme was completed, Tasso had done his best work as a poet.  The misfortunes which began to gather round him in his thirty-first year, made him well-nigh indifferent to the fate of the poem which had drained his life-force, and from which he had expected so much glory.  It was published without his permission or supervision.  He, meanwhile, in the prison of S. Anna, turned his attention to prose composition.  The long series of dialogues, with which he occupied the irksome leisure of seven years, interesting as they are in matter and genial in style, indicate that the poet was now in abeyance.  It remained to be seen whether inspiration would revive with freedom.  No sooner were the bolts withdrawn than his genius essayed a fresh flight.  He had long meditated the composition of a tragedy, and had already written some scenes.  At Mantua in 1586-7 this work took the form of Torrismondo.  It cannot be called a great drama, for it belongs to the rigid declamatory species of Italian tragedy; and Tasso’s genius was romantic, idyllic, elegiac, anything but genuinely tragic.  Yet the style is eminent for nobility and purity.  Just as the Aminta showed how unaffected Tasso could be when writing without preconceived theories of heightened diction, so the Torrismondo displays an unstrained dignity of simple dialogue.  It testifies to the plasticity of language in the hands of a master, who deliberately chose and sustained different styles in different species of poetry, and makes us regret that he should have formed his epic manner upon so artificial a type.  The last chorus of Torrismondo deserves to be mentioned as a perfect example of Tasso’s melancholy elegiac pathos.