On this journey Mohammed for the first time came in touch with Christianity, and was surely impressed by the national and social customs of Christians; and being a bright boy, he was easily able to see the difference between the habits and religion of his own nation and those of the Christians. It was after this journey that he was anxious to reform the dreadful idolatry and wicked ways of the Arabian people. From the age of twelve to twenty he lived in the usual manner of the boys of his day, tending sheep on the hillsides and valleys of Mecca, and he was so honest and pure and fair during these years, and such a contrast to those around him, that everybody gave him the name I told you of—Al Amin, _i. e._, “the faithful.” During this time, too, he learned something of what war was like, for he went with his uncles on two expeditions to fight against another tribe. When Mohammed was twenty-five years old, his uncle suggested that he should take charge of a caravan for a rich lady living in Mecca, and trading products of Mecca for other things from Syria and other parts of Arabia. On this journey Mohammed again came in contact with Christians and Jews, and he must have noticed, too, how, while professing to serve and love the one true God, they always seemed to be quarrelling about their religion. Perhaps he saw the truth in both systems and afterwards thought he could make out of them one simple creed and unite all mankind in the worship of the only true God. After his return from this trip, he was married to Khadijah, by whom he had been employed as camel driver, making zigzag journeys across the country to sell and exchange his merchandise. After his marriage he lived happily, so we are told, until his fortieth year, when he began to have dreams, and became persuaded that God had called him to be a prophet. Many verses of the Koran were recited and written down. Mohammed wanted most of all at this time that his countrymen should put away their idols and worship only Allah, but some of them were very angry and would have killed him, if he had not hidden. Mohammed and Khadijah had six children, but most of them died when they were young. His daughter Fatimah, when she was old enough, was married to her adopted brother, Ali; her name is very much honoured and used by Moslems everywhere.