I'm sorry - I don't know the number of this sonnet. If I recall correctly, I found it online accompanied by a very clunky translation, and was sufficiently enraged to re-do it from scratch. I hope this works better!
Per fare una leggiadra sua vendetta
et punire in un dí ben mille offese,
celatamente Amor l’arco riprese,
come huom ch’a nocer luogo et tempo aspetta.
Era la mia virtute al cor ristretta
per far ivi et ne gli occhi sue difese,
quando ‘l colpo mortal là giú discese
ove solea spuntarsi ogni saetta.
Però, turbata nel primiero assalto,
non ebbe tanto né vigor né spazio
che potesse al bisogno prender l’arme,
overo al poggio faticoso et alto
ritrarmi accortamente da lo strazio
del quale oggi vorrebbe, et non pò, aitarme.
To wreak his grim revenge with charm and grace,
in one swift day to settle our long score,
Love secretly took up his bow once more,
as an assassin waits his time and place.
My power was constrained within my heart
to make defence both there and in my eyes;
the mortal blow descended from the skies
where blunt had fallen every other dart.
And so, confounded in that first attack,
it had not strength not space to make a stand
and seize its weapons in the hour of need,
nor up the high steep hill to draw me back
strategically from misfortune's hand,
whence it would save me, but cannot indeed.