Meanwhile he must not go too fast, and so Mohammed 'with the stolid patience which in Europe belongs only to the greatest, and in Asia to everybody,' waited the year in peace--he spent it, in fact, making his own domestic arrangements, strengthening his own position, organizing the practice of the Faith. The empty plot of ground at which Al Caswa halted was bought, and upon it arose the first Mohammedan mosque. Beside it were built two cottages, one for Saudah, the wife whom he had married within a few weeks of Khadîjah's death, and the other for Ayesha, the child of Abu Bakr, only nine years of age, whom he now took as a second wife. [Illustration: THE OBSERVANCE OF PRAYER. '_Typical of Mohammedanism in every century and in every clime._] The mosque was the first visible centre of Islam. As it rose he built, too, the pillars of Mohammedan religious practice, on which Islam has rested ever since. Friday was established as the day of assembly when he preached himself to the people of Medina from a pulpit built of tamarisk trees, by the outside wall of the mosque. The duty of ceremonial washing (lustration as it was called) as a preliminary to prayer was enjoined, and {69} most typical of Mohammedanism in every century and in every clime, the observance of prayer at five stated times in the day. The prayers, accompanied by a series of four genuflections, were to be said facing originally towards Jerusalem and later towards Mecca. These prayers soon became the habit of 'the faithful.' To-day they are said in all the great mosques of the East. They are recited along every trade route of the Sahara and Soudan where the Arab drives his lonely caravan; they are used by saint and ascetic, brigand and slave-dealer alike--wherever men call themselves after the name of the Prophet. But none of these provisions so well illustrate Mohammed's judgment and his æsthetic sense as his institution of the call to prayer by the human voice, and not by Jewish trumpet or Christian bell. It is said that the suggestion came from Omar. He communicated it to the Prophet, who cleverly replied that a special revelation to that effect had just been given him. Anyhow, the negro slave, Bilâl, was soon shouting the call from the highest turret in Medina, and the weird music of the muezzin's voice from myriads of minarets {70} still floats across the air from Cape Verde to Muscat, from Suez to Nankin, summoning one out of every seven of the entire human race to worship five times a day. _'God is most great! I witness that there is no God but God, and Mohammed is the Apostle of God! Come to prayer! Come to salvation! God is most great! There is no God but God!'_ At dawn is added the very human reminder, '_Prayer is better than sleep!_' [Sidenote: Mohammed's Followers in Mecca.]