There have been books written about the history of coffee. It has a long and somewhat interesting history. Here is North Coast Coffee's short version.

There is a legend that a long time ago (some have it around the year 800 BC, others around 500 AD), an Ethiopian goat herder by the name of Kaldi, noticed that some of his goats were frolicking about much more than they normally did. He saw that they had been eating something from a bush with dark shiny leaves. Upon closer inspection, he saw that they had been eating the red berries from the bushes.

Kaldi ate some of the coffee cherries himself, and, being amazed at the stimulating effect that they had, brought some to the local monk.

The monk boiled the cherries and made a beverage that was strong and bitter. Like Kaldi, the monk felt the effect of the caffeine in the drink and liked it very much. The beverage soon became popular as the monks found that it helped keep them awake during long hours of prayer.