According to Albert Jack's Penguin Food book, "What Caesar Did for My Salad," the Caesar salad did not get its name from Roman times. Its origin is much more recent and dates back to the 1920s.
At that time, a man named Caesar Cardini owned a restaurant in Tijuana, near the border with the United States. On a national holiday, July 4, 1924, it is said that the Cardini's restaurant was so successful that they sold out of everything on their restaurant menu. To keep the restaurant running, Caesar Cardini took it upon himself to make a salad from whatever ingredients he had on hand in the refrigerator: lettuce, croutons, parmesan, eggs, olive oil, lemon juice, pepper and Worcestershire sauce.
It is said that "probably to hide the simplistic nature of the salad, Mr. Cardini would have brought it to his guests and covered it with a thick sauce".
The current recipe, with its addition of chicken and sometimes bacon, differs from the original version in its very spirit: the original Caesar salad is a refrigerated "bottom of the drawer", while today's is an excellent primi piatti.