What was Charlie Nagreen's hamburger-related nickname?

Charlie Nagreen’s hamburger-related nickname was “Hamburger Charlie.”

Nagreen was a Wisconsin food vendor associated with the Seymour Fair and became locally celebrated as a claimant to the hamburger’s invention. The nickname distinguished him from the many other people and places later credited with creating the sandwich.

According to the Seymour account, Nagreen sold meatballs at the 1885 fair. Because customers wanted to walk around while eating, he flattened the meat and placed it between slices of bread. The portable format reportedly made the food more successful, and he continued selling hamburgers at the fair for decades.

The hamburger’s origin is disputed. Other claims involve Louis Lassen of Louis’ Lunch, the Menches brothers in Ohio, Fletcher Davis in Texas, and several other vendors. “Burger King” is a restaurant chain, not Nagreen’s nickname, while “Patty Pete” and “Slider Sam” are fictional-sounding alternatives.