Ouzo history is somewhat murky, but some claim it may date back in one form or another to ancient times. Its precursor is tsipouro (known by some Easterners as raki), a drink distilled throughout the Byzantine Empire and continued throughout Ottoman times. Traditionally, Tsipouro is said to have been the pet product of a group of 14th century monks living in a monastery on holy Mount Athos. One version of it is flavored with Anise. It is this version that eventually came to be called Ouzo.
Ouzo is traditionally mixed with water, until it takes on a murky, white demeanor, and served with ice in a small glass. Ouzo can also be drunk, straight, from a shot glass. The European Union now recognizes ouzo, as well as the Greek drinks tsipouro and tsikoudia, as products with a protected designation of origin, which prohibits makers outside Greece from using the name.