In the 3rd century BC, Alexandrian critics - the so-called Chorizontes ('dividers') - believed that the two epics were written by two different authors. It was also suggested that some parts of the Epics were added at a later time. The dispute was revived in modern times at the end of the 17th century (the problem became known as the 'Homeric question'). At that time, several ideas about the actual authorship of the 'Iliad' and the 'Odyssey' emerged.
The German philologist Friedrich August Wolf proposed that the two great epics were created through the compilation of folk songs, the work of many wandering singers, which were collected into larger wholes after years of oral tradition. Another concept - the theory of song - suggested that the Iliad was created by combining eighteen songs by different authors during the time of Pisistatus. An extension of this was that Homer was credited with creatively combining these original works. A third concept - the theory of compilation - was developed under the influence of the previous theories and suggested that Homer collected and used pre-existing works of oral poetry to write his poems, which he linked together with a coherent plot.
Modern analysis suggests that both the Iliad and the Odyssey are the result of a long development of Greek epic poetry passed down orally over many years. The resulting output, in the form of heroic songs and poetic technique, was used by one or more poets to create a great and elaborate composition.