User: Given this reference text, how was the cheeseburger invented?
Assistant: The cheeseburger was invented after the late 19th century after the vast grasslands of the Great Plains opened up for cattle ranching. Once this happened Americans consumed meat daily of which ground beef/hamburger meat was the most affordable.  In 1920, adding cheese to the hamburger meat popular.  It is said that Lionel Sternberger invented the cheeseburger in 1924 while working at his father's sandwich shop.