the battle-field. Immediately after the victory Mahomet proceeded to besiege Ṭā'if, but the inhabitants of the town defended it with unusual vigour and the Muslims were soon obliged to retreat. This discomfiture, however, does not seem to have injured the Prophet's cause, for a few days later the majority of the Hawāzin announced their intention of adopting Islām. The new converts received back their wives and children, but the rest of the booty taken at Ḥunain was distributed among the victors. Nor did the people of Ṭā'if long remain faithful to their old religion; after an interval of about half a year they entered into negotiations with the Prophet and finally submitted to his authority.
In the autumn of this year (630) a report reached Medina that a great Byzantine army was advancing into Arabia from the north-west. The report was certainly false; whether Mahomet believed it or merely utilised it as a pretext for a raid it is impossible to say. In any case he collected all his forces and marched with them as far as Tabūk, which is about 300 miles to the north-west of Medina. As no Byzantines appeared to oppose him, the only result of his expedition was the subjugation of some small Jewish and Christian settlements in the north of Arabia. Both Jews and Christians were allowed to retain their property and the right to profess their religion, on condition that they paid a yearly tribute, the amount of which was fixed in each case by a special treaty.
On the occasion of the next annual Pilgrimage, in the spring of 631, Mahomet issued a solemn proclamation, now contained in chap. ix. of the Koran, whereby heathens were thenceforth excluded from participation in the Pilgrimage and the cult of the Ka'ba. The following year the Prophet himself performed the Pilgrimage and finally settled the details of the ceremonies to be observed in connexion with it. During all subsequent ages this institution, notwithstanding its purely heathen origin, continued to be the great bond whereby Muslims of all parties were held together. Such a result could not have been attained by the Koran alone or by any abstract creed however carefully formulated.
Another matter which he undertook to regulate at about the same time was the sacred Calendar. Till then the Arabs, so far as can be ascertained, had reckoned by solar years but by lunar months, that is to say, they followed the practice, which appears to have been common among the Semitic nations, of inserting an intercalary month from time to time so as to adjust the year to the seasons. But as their notions of astronomy were of the crudest sort, much confusion naturally arose. This the Prophet, who was equally ignorant, endeavoured to remedy by announcing, in the name of God, that thenceforth the year was always to consist of twelve lunar months. Accordingly the Muslim year was altogether dissociated from the natural seasons, for
