Pu-erh tea can be traced back to the Yunnan Province during the Eastern Han Dynasty (25-220CE). Trade in Pu-erh tea began in the Tang Dynasty, became famous during the Ming Dynasty and was popularized in the Qing Dynasty.
Pu-erh was transported by mules and horses in long caravans along established routes that became known as the Tea Horse Roads. Traders would barter for tea in the markets of Pu-erh County and then hire the caravans to carry the tea back to their respective homes.
The increasing demand for a tea that could be easily transported and did not spoil on long journeys sent suppliers on a frenzy to come up with ways to preserve the tea. It was found that with fermentation of the leaves, the tea not only kept fresh but it actually improved with age. People soon discovered that pu-erh also helped with digestion, provided other nutrients to their diet, and because it was so affordable, it quickly became a popular household amenity. Pu-erh tea was highly prized and it became a powerful tool for bartering amongst traveling merchants.