Potato and leek soup is said to have originated in France in the late 18th century, having been developed by a French pharmacist Antoine-Augustin Parmentier. Up until then, potatoes had been regarded as only being fit for pig food and were thought to cause leprosy in humans. Apart from promoting potatoes as a food source in France and Europe, Parmentier is also remembered for establishing the first smallpox vaccination campaign under Napoleon's rule. He also studied methods of conserving food, including refrigeration.