I actually knew about the tariff laws (though not, as gssixgun says later, that it isn't reliable) but I wondered if there was a less formal, earlier date for adding Sheffield. Based on this thread, I'm guessing the answer is "not really."
Originally Posted by bouschie
Not sure on Sheffield but they added England about 1890/1891.
Go to strazors.com and click on articles where you find info on history and tariff act.