1752: The sandwich is invented by John Montagu, the Fourth Earl of Sandwich.
1792: John Pearson establishes America's first commercial bakery in Newburyport, Mass., to make "pilot bread" — a tough and durable biscuit to sustain sailors on long voyages.
1837: "Miss Leslie's Directions for Cookery" gives an American recipe for ham sandwiches.
1883: Oscar F. Mayer leases a failing meat market in Chicago, and, with the help of his brothers, makes it a success within 5 years.
1884: The first "Boston Cooking School Cook Book" gives sandwich recipes with a variety of fillings: cooked ham, corned beef, tongue, lobster, chicken salad and raw beef.
1894: The club sandwich — chicken breast and bacon, tomatoes and lettuce layered between two or three slices of toasted bread — may have first appeared at the exclusive Saratoga Club-House in upstate New York.
1903: James L. Kraft begins a wholesale cheese business in Chicago.
1903: The oldest recipe for the club sandwich is published in the "Good Housekeeping Everyday Cook Book," by Isabel Gordon Curtis.
1918: The French dip sandwich is created by French immigrant Philippe Mathieuat at Philippe the Original sandwich shop in downtown Los Angeles.
1920: Wonder Bread, "The new wrapped loaf," hit the markets.
1921: The Pig Stand, a drive-in sandwich restaurant using car-hop service, opens near Dallas-Fort Worth. It is the forerunner to the fast-food industry.
1926: The Toastmaster (a pop-up toaster) is introduced for the American home.
1922: First shelf-stable peanut butter is developed.
1928: Commercial bread slicer is invented in Chillicothe, Mo.
1930: Pre-sliced bread is marketed by Wonder Bread. By 1933, 80 percent of the bread sold in the United States is pre-sliced.
1930: The Philly cheese steak sandwich is first served at Pat Oliveri's hot dog stand in Philadelphia.
1933: Kraft Miracle Whip premieres at the Chicago World's Fair. A patented "emulsifying machine" blends mayonnaise with less expensive salad dressing.
1937: SPAM canned lunch meat is launched.
1950: Kraft Deluxe process cheese slices are introduced in the United States.
1964: Blimpie sandwich shops are founded in Hoboken, N.J., by Tony Conza and two high school friends.
1965: Fred DeLuca, an ambitious 17-year-old, opens Pete's Super Submarines — forerunner to the Subway sandwich chain — in Bridgeport, Conn.
1981: Quizno's opens its first store in Denver, Colo.
2002: Chicken Florentine Panini sandwich wins the Pillsbury Bake-Off's $1 million grand prize for Denise Yennie of Tennessee.
2004: To keep up with the low-carb diet craze, Subway launches two Atkins-approved sandwich wraps.
2004: Chef Todd Mark Miller makes waves with his $100 Philly cheese steak sandwich, served at the posh Barclay Prime steak house in Philadelphia.
Souces: "American Sandwich," by Becky Mercuri; "What's Cooking America," by Linda Stradley (whatscookingamerica.net); "Dining Through the Decades," by Valerie Phillips, and company histories.