Black tea was another fortuitous accident in tea history. In the mid 1600s, a tea producer in the Wuyi Mountains had layed out leaves to dry, when an invading army camping nearby forced them to go into hiding. By the time the army had passed by, the tea leaves had fully oxidized. The tea producer thought their tea was ruined, so they tried to salvage it by smoking it over pine needles to mask the flavor. They couldn't find anyone who would buy the tea, until they found some Portuguese traders. Western traders were desperate to buy tea, but few would sell such a precious commodity. The traders brought the 'ruined' tea to Europe, where it became hugely popular.
The Chinese tea makers quickly increased production of what they called hong cha - 'red tea', meaning the color of the brew. The English called it 'black tea', based on the leaves as compared to green. This has created a naming confusion, as the sixth type of tea, often called pu'er, is a type known in China as hei cha, which means - you guessed it! - 'black tea'.
Desperate to control their own tea production, the British tried for many years to smuggle tea plants out of China. When they eventually succeeded, they found only one place where their stolen cuttings would flourish: Darjeeling, India. Darjeeling tea is still based on the sinensis varietal, but another varietal of tea plants grew wild in Assam, and were more suitable for growing elsewhere. The assamica varietal now grows in many countries around the world.
The original black tea, Zhengshan Xiaozhong (or Lapsang Souchong, as the English called it) is still a popular Chinese black tea, for it's smokey flavor. In addition, black tea from Qimen (called Keemun in the West) is well liked for it's fruity flavors. Within China, black teas from Yunnan and Sichuan are highly regarded. Jin Jun Mei, also from the Wuyi Mountains, is made from only budding leaves picked in early Spring, and is one of the most prestigious teas in the world.