I read once that some 17th century Italian came on a Shakespeare work, couldn't imagine it presented any way other than sung, and invented opera thereby.
I haven't heard that one. As far as I can see, the only 17th century Shakespearean operas were British: The Tempest
(1674) by various composers, and Purcell's The Fairy-Queen
(1692). There were several more in the early 18th century, but the first Italian one seems to have been Ambleto
(1706) by Francesco Gasparini.