In Tasso's Gerusalemme Liberata, Canto Primo, Octave 58 we see:
Ma il fanciullo Rinaldo, e sovra questi e sovra quanti in mostra eran condutti, dolcemente feroce alzar vedresti la regal fronte, e in lui mirar sol tutti. L'età precorse e la speranza, e presti pareano i fior quando n'usciro i frutti; se 'l miri fulminar ne l'arme avolto, Marte lo stimi; Amor, se scopre il volto.
I know Spanish, French and some Latin good enough to deduce the meaning of most of words here, but those from the title still remain a mystery for me. I take it alzar here might be a relative of alzare and mean something like 'ampiezza', but could this be a noun as well? Or a shortened form of the verb?
What is avolto? A participle, an ajective, or a noun?
And, last but not least, what is pareano? Does it stand for 'similar to' (like French pareil) or something different?