“To the poems of the Horton period belong also the two pieces
‘L’Allegro’ and ‘Il Penseroso,’ and ‘Lycidas.’ He was probably in the
early stage of acquiring the language when he superscribed the two first
poems with their Italian titles. For there is no such word as
‘penseroso,’ the adjective formed from ‘pensiero’ being ‘pensieroso.’
Even had the word been written correctly, its signification is not that
which Milton intended,—viz., thoughtful or contemplative, but anxious,
full of cares, carking.”
_Milton as a Botanist_