Poetry was a powerful means of communicating in the ancient Greco-Roman world; poetry was often sung, as well as recited and read. Th e earliest surviving Greek works are poems, recognisable through certain formal structures, most notably metre. In ancient Greece, poetry was usually understood as being 'in metre' (emmetros), while discourse 'without metre' (aneu metrou) is prose (see, e.g., Plato Phaedrus 252b6; 258d10-11).