Our research for "Carnival Glass, the Magic & The Mystery" revealed a date of 1913 for the first general advertising of Fenton's Peacock & Grape items.
As for the "Thistle & Thorn"....well, though some people like to attribute it to Sowerby, I have never been able to find any positive attribution. I feel (for lots of reasons) that it is an English product, and my own preference is to state "maker unknown, possibly English".
Glen