The sandwich as we know it was popularized in England in 1762 by John Montagu, the 4th Earl of Sandwich.

Montagu loved cards games and could spend hours on end playing. During a particularly long binge, he asked the house cook to bring him something he could eat without getting up from his seat...

...and the sandwich was born. Montagu enjoyed his meat and bread so much that he ate it constantly, and as the concoction grew popular it took on the Earl’s name.