Sweet potatoes are one of the oldest vegetables known to mankind. Scientists believe that they were already cultivated in central America thousands of years ago. Their first appearance is dated back to 750 B.C. in Peruvian records. They first came to Europe brought by Christopher Columbus, who discovered them on his journey in 1492. He liked the vegetable so much that on his fourth voyage, he took some home to grow in Europe.
As sweet potatoes were very well accepted in Spain, the Spanish conquerors took them on their journeys. The Spanish seamen brought it over to China in the 16th century and helped spreading it through Asia, Africa, and Latin America during the 17th and 18th centuries.
They became not only famous as a food source but also as a source of starch and alcohol. The fact that they are easy to cultivate helped the orange root to become popular.