 There is no evidence as to the stringing of the Greek lyre in the heroic age.Plutarch says that Olympus and Terpander used but three strings to accompany their recitation.As the four strings led to seven and eight by doubling the tetrachord, or series of four tones filling in the interval of a perfect fourth, so the trichord is connected with the hexachord or six-stringed lyre depicted on many archaic Greek vases.