Greek vocal music extends far back into ancient times where mixed-gender choruses performed for entertainment, celebration and spiritual reasons. Instruments during that period included the double-reed aulos and the plucked string instrument, the lyre, especially the special kind called a kithara. Music played an important role in the education system during ancient times. Boys were taught music from the age of six. Later influences from the Roman Empire, Middle East, and the Byzantine Empire also had effect on Greek music.