various other foreign potentates, summoning them to recognise his divine mission. But the evidence for this story is by no means satisfactory, and the details present so many suspicious features that it may be doubted whether the narrative rests on any real basis.
Soon after his return to Medina, Mahomet set out on an expedition against Khaibar, where the banished Banu-n-Naḍīr had taken refuge. The Jews, as usual, shrank from a conflict in the open plain and shut themselves up in their fortresses, which fell one by one into the hands of the Muslims. The vanquished were compelled to surrender all their wealth, which was very considerable, but they were permitted to remain at Khaibar as cultivators of the soil, on condition that half of the produce should be annually made over to the Muslim authorities. This is the first instance of an arrangement which was afterwards adopted in most parts of the Muslim Empire where the population consisted of non-Muslims.
Early in the year 629 Mahomet, with about 2000 followers, carried out his project of visiting Mecca as a pilgrim, in accordance with the treaty of Ḥudaibiya. For the stipulated three days he was allowed to occupy the sacred city and to perform the traditional ceremonies in the sanctuary. The scene must have been a curious one, never to be repeated — the great preacher of monotheism publicly doing homage at a shrine filled with idols. The sight of Mahomet's power deeply impressed the Meccan aristocracy, and two of the most eminent among them, Khālid ibn al-Walīd and 'Amr ibn al-'Aṣ, took the opportunity of going over to Islām. Both of these men afterwards played a prominent part in the building up of the Muslim Empire.
A few months later Islām for the first time came into conflict with the great Christian power against which it was destined to struggle, with scarcely any intermission, for a period of eight centuries. In the autumn of the year 629 Mahomet despatched a force of 3000 men, commanded by his adopted son Zaid ibn Ḥāritha, to the north-western frontier of Arabia. The reason which most of the historians assign for this expedition is that a messenger sent by the Prophet had been assassinated, a year earlier, by an Arab chieftain named Shuraḥbīl, who owned allegiance to the Byzantine Emperor. But since Ibn Iṣḥāḳ, the oldest writer who records the expedition, does not allege any pretext for it, the correctness of the aforesaid explanation is at least doubtful. In any case it is difficult to believe that Mahomet contemplated an attack on the Byzantine Empire, for ignorant as he was of foreign countries he must have been aware that an army of 3000 men would be wholly inadequate for such a purpose. When the Muslim force reached the neighbourhood of the Dead Sea, they found themselves, to their great surprise, confronted by a much larger army composed partly of Byzantines and partly of Arabs subject to the Emperor. After some hesitation Zaid ibn Ḥāritha determined to fight. The battle took place at Mu'ta,
