Samuel Gawith sounds like a good guess to me. For U.S. blends, Prince Albert and Granger might be pretty old. There might be a blend or two in the Iwan Ries inventory that would go way back, although I think their venerable Three Star Blue only goes back in its present form to the 1950's. As someone pointed out recently, blends change to some degree with every season of tobacco growing in every region of the world, so we are only talking about the longest existing brands. Really old ads in newspapers and magazines might supply other clues, at least well back into the 19th Century. Many fairly recent brands or revived brands like to give the impression of antiquity, so that also confuses things.