Keeping on telling her story, Armida says that she absolutely refused to marry that ugly and base cousin of hers. Her uncle and tutor wasn't glad at all . . . [5: 50]
Partissi al fin con un sembiante oscuro,
Onde l'empio suo cor chiaro trasparve;
E ben l'historia del mio mal futuro
Leggergli scritta in fronte allhor mi parve.
Quinci i notturni miei riposi fûro
Turbati ogn'hor da strani sogni e larve,
Et un fatale horror ne l'alma impresso
M'era presagio de' miei danni espresso.
"He finally left, with a darkened countenance through which his impious heart clearly showed; and it seemed to me to be able to read the whole story of my looming evil on his forehead. From then on, my sleeps have been upset by strange dreams and spectres, and a fatal horror, impressed in my soul, provided an evident omen of my dangers."
"To read something on someone else's forehead" or "to have (or have not) something written on one's forehead" are common Italian phrases still nowadays.
The episode acquires a witty nuance if we remember that Armida is 'actually' the daughter of a mermaid, and we compare these verses with Dante, Purgatorio 19: 19 ff, when he dreams of a mermaid. Here, a mermaid has a dream, a nightmare indeed!
Fatal dreams are commonplace throughout the history of literature, but in Tasso's works they play a more special and disturbing role.