Chocolate was a favorite drink of the Maya, the Aztecs and other Mesoamerican peoples long before the Spaniards “discovered” it and brought it back to Europe. Archaeological evidence suggests that chocolate has been consumed for at least 3,100 years and not just as food: the Maya and other pre-Columbian cultures offered cacao pods to the gods in a variety of rituals, including some that involved human sacrifice.

But it was an Irish Protestant man who had what might be the most pivotal idea in chocolate history. In the 1680s Hans Sloane, a physician and naturalist whose estate—a vast collection of books and natural specimens—kick-started the British Museum, was in service to the British governor of Jamaica, collecting human artifacts and documenting local plants and animals. Sloane realized that the bitter local chocolate beverage would become much more palatable to his taste when mixed with milk. He later patented his invention. Although many had been enjoying chocolate made with hot water, Sloane’s version quickly became popular back in England and elsewhere in Europe. Milk also became a favorite addition to solid chocolate, and today around two thirds of Americans say they prefer milk chocolate to dark chocolate.

Chocolate’s positive health effects are by now well documented. Antioxidants such as polyphenols and flavonoids make up as much as 8 percent of a cacao bean’s dry weight, says Joe Vinson, a chemist at the University of Scranton. Antioxidants neutralize highly reactive molecules called free radicals that would otherwise damage cells. And it is not a coincidence that the cacao tree (and other antioxidant-rich plants such as coffee and tea) would originate from low latitudes. “Things that have high levels of antioxidants tend to grow in places near the equator, with lots of sun,” Vinson says. The sun’s ultraviolet rays break up biological molecules into free radicals, and these plants may produce antioxidants to better endure the stress.

Although eating too much chocolate results in excessive calorie intake, human and animal studies have shown that moderate chocolate consumption can have beneficial effects on blood pressure, slow down atherosclerosis and lower “bad” cholesterol. Chocolate may also be good for the mind: a recent study in Norway found that elderly men consuming chocolate, wine or tea—all flavonoid-rich foods—performed better on cognitive tests.