Irbil, or Arbela, is two days' journey from Mosul. See Saadyana, J. Q. R., vol. XIV, p. 503, and W. Bacher's note, p. 741.
For a full account of Mosul and other places here referred to, see Mr. Guy Le Strange's The Lands of the Eastern Caliphate, 1905, also Layard's Nineveh and its Remains and Nineveh and Babylon. Layard carefully examined Nebbi Junus, which is held in great veneration by the Mussulmans, and came to the conclusion that the tradition which places Jonah's tomb on this spot is a mere fable (p. 596). It will be seen that Benjamin speaks of the Shrine as a Synagogue. At Alkush near Mosul the tomb of Nahum is pointed out, and the Arabs say that after Jonah had fulfilled his mission to the people of Nineveh they relapsed into idolatry. Then Nahum denounced the city and was slain by the populace, who proclaimed him and Jonah to be false prophets, since the doom the latter foretold does not come to pass, See Schwarz, Das Heilige Land, 1852, p. 259, identifying Kefar Tanchum near Tiberias with Nahum's burialplace
As to Jewish seats of learning in Babylon refer to Dr. Krauss's Article "Babylonia" in the Jewish Encyclopaedia; see also Guy Le Strange, p. 74, who suggests that Pumbedita means "mouth of the Badat canal." Cf. J. Q. R., XVII, p. 756.
Hadara goes under the name Alhathr or Hatra. There must exist great doubt as to whether Benjamin had personally satisfied himself as to the Jewish population he gives for this and the other places he tells of, till he comes to Egypt. Up to this point the Traveller has always appeared to under-estimate the Jewish population. Henceforth it will be found that he gives apparently exaggerated figures,—and this lends colour to the view that Benjamin did not proceed beyond Ispahan, but found his way thence direct to Egypt. The statements concerning the intervening places must therefore be taken to have been based upon hearsay information. Pethachia's remarks are significant: "In the land of Cush and Babel are more than sixty myriads of Jews; as many are in the land of Persia. But in Persia the Jews are subject to hard bondage and suffering. Therefore Rabbi Pethachia visited only one city in Persia." (Dr. Benisch's edition, p. 19.)
The Caliphs of the Abbaside Dynasty traced their descent from Mohammed. Benjamin here refers to the Caliph El Mostanshed. The Caliph is aptly compared to the Pope. In addition to his temporal authority at Bagdad, he exercised as Leader of the Faithful—Emir al-Muminin—religious authority over all Mohammedans from Spain to India. At a later time the vizier arrogated all authority to himself, and the Caliph spent his time either in the mosque or in the seraglio.