The earliest reports of people enjoying flavored ice desserts come from the Romans and the Chinese. Marco Polo returned from his famous expedition with fruit-flavored ices, reporting that Asians had been making them for thousands of years. These delicacies became popular in France in the 1500s, but only among royalty. Over the next few centuries, the process of making them evolved from hauling mountain ice to salt/ice freezing methods. Cream was introduced as an ingredient, and by the 1700s, people were enjoying a dessert that was very similar to today's ice cream.
The hand-cranked ice cream freezer was first developed by Nancy Johnson in 1846. Ice was readily available from large warehouses in that era, so ice cream became a treat that could be enjoyed by almost anyone, not just the rich. Ice cream making was revolutionized again in 1851, when Jacob Fussel started the first wholesale ice cream manufacturing operation in Baltimore, Maryland. Fussel's dairy business had excess cream and he couldn't figure out what to do with it. He tried using it to make ice cream, and before long his ice cream business outsold the rest of the dairy.
The business slowly evolved for the next few decades. Manufacturing methods and ingredients improved, while refrigeration technology became cheaper and more efficient. By the 1920s, home refrigerators and freezers became more common, which gave the ice cream industry another boost. Sugar was rationed in the US during World War I, but the ice cream industry convinced the government that ice cream was an "essential food”. Ice cream factories were allotted sugar rations and production continued.
Ice cream increased in popularity until the Depression years caused a drop in sales for virtually all non-essential goods. Sales increased in the years leading up to World War II before leveling off in the post-war years. The rise of the giant supermarket created demand for cheaper, mass-produced ice cream, but quality suffered. The 1960s saw a resurgence in "premium" ice cream, while the following decades saw the market fragment into low-fat varieties for the health-conscious, including frozen yogurt, fruit bars, ice milk, fat-free ice cream, and dozens of other varieties. However, ice cream still makes up about 60 percent of the market share among frozen desserts. While ice cream is enjoyed worldwide, it has become an American tradition.
（来源：howstuffworks.com 实习生吴昭文 英语点津 Annabel 编辑）