While waiting for a more targeted answer, you may enjoy the following -

When did Italians become considered White with answers from now deleted accounts.

How did Italians become White and answers from /r/caffarelli

When did Italians, Irish, and Poles become White and a mass link post by /u/Searocksandtrees

ow well did the European immigrants to the United States of America who weren't of north and north western stock fit into the dichotomy of black-white? and the answer by /u/VetMichael that expands in to other groups as well.

And WHen and how did ethnic groups become White that covers Irish and Italians, and several neat posts but I'd point your attention to /u/Armadillo19 to start, though there's a "fun" quote way down the chain, attributed to Benjamin Franklin that argues the only white people are English and Saxon and no one else.

Which leads me to add one Remark: That the Number of purely white People in the World is proportionably very small. All Africa is black or tawny. Asia chiefly tawny. America (exclusive of the new Comers) wholly so. And in Europe, the Spaniards, Italians, French, Russians and Swedes, are generally of what we call a swarthy Complexion; as are the Germans also, the Saxons only excepted, who with the English, make the principal Body of White People on the Face of the Earth. I could wish their Numbers were increased. And while we are, as I may call it, Scouring our Planet, by clearing America of Woods, and so making this Side of our Globe reflect a brighter Light to the Eyes of Inhabitants in Mars or Venus, why should we in the Sight of Superior Beings, darken its People? why increase the Sons of Africa, by Planting them in America, where we have so fair an Opportunity, by excluding all Blacks and Tawneys, of increasing the lovely White and Red? But perhaps I am partial to the Complexion of my Country, for such Kind of Partiality is natural to Mankind.