According to legend, the custom of tea drinking began around 2737 B.C. with the Ancient Chinese Emperor Shen Nung. The Emperor, a man of science and father of Chinese medicine, had ruled that all water be boiled before drinking. This being his habit, one day leaves of a black tea shrub fell into the boiling water. The Emperor upon tasting the drink, proclaimed it heaven-sent.
No one can say how the leaves fell or were blown from that shrub into the Emperor’s water. Heaven-sent, serendipitous scientific discovery, or happy accident? The popularity of tea spread to Japan and the Far East, and eventually throughout the world.
As noted from http://www.lifetimetv.com