In the seventeenth and eighteenth centuries, food was a classic marker of identity in Europe. In the nineteenth-century “Age of Nationalism” cuisine became a defining symbol of national identity. The Industrial Revolution brought mass-production, mass-marketing, and standardization of food. Factories processed, preserved, canned, and packaged a wide variety of foods, and processed cereals quickly became a defining feature of the American breakfast. In the 1920s, freezing methods, cafeterias, and fast food restaurants emerged.