Homer may or may not have been a historical individual. He is credited with the authorship of two great ancient Greek epics, the Iliad and the Odyssey. Twentieth-century scholarship believes these two texts reflect a long tradition of oral composition; bards working in the tradition learned a vast array of formulas they used to tell traditional stories, inventing the poems anew at least in some details at every telling. The two poems must have attained more or less their present form by the eighth century B.C.E. and started to circulate as texts attributed to Homer not long thereafter, thanks to the importation and adaptation of alphabetic writing.