I've noticed that people often say that a Sheffield blade was manufactured before 1891 if it's not marked "England". It seems pre 1892 would be more accurate as that's when the Madrid accord was first enforced. I'm sure many blades were produce in 1891 before the agreement was finalized. I've also been trying to find a list of countries that were involved in the original 1891 agreement as I understand the U.S. Was not. Was France in on the deal?