But at the beginning of his preaching—or prophesying—Mahomet had hard work to make his doctrine accepted, and himself acknowledged as the prophet of the one and only God, even among his own people. He had to fly from his native city of Mecca to the neighbouring Medina. After a while he found supporters there, and by degrees they became so many that he was able to go back and take Mecca. Then, again by degrees, he was joined by so many of the Arabian tribes that he was able to send armies beyond the bounds of Arabia, into Syria northward. They suffered defeat and check at times; but on the whole they were extraordinarily victorious.
For their success there were several causes, all quite easy to understand. They were a hardy people, accustomed to meagre fare and to hard living in the desert. They were very fine horsemen. The religion which their prophet preached to them promised untold joys in Paradise for those who died fighting against the enemies of Islam. (Islam was the prophet's name for the faith which he preached.) An intense belief in this happy future, after death, made them fearless in battle. Then they were a very poor people, and those against whom Mahomet sent them were far richer, and to the Moslem soldier loot from the enemy never was forbidden. They seem to have had a certain sense that some justice and mercy were due to the conquered, for the rule was that only four-fifths of the loot taken became the property of the conquerors. The conquered were left with a fifth.
And most of those against whom they went at first were weak, owing to lack of discipline and absence of strong government. The forces of the Eastern Empire in Asia Minor and of the Persians had been weakened by continuous fighting against each other. Syria had been so hammered between the two that it had little strength of its own. Egypt was feebly held. But it was not till after the death of the prophet that the armies carried the green flag of Islam east and west; and for a while after his death the succession to his religious leadership was much disputed.
It may occur to you to ask what need there was for a successor to such a position as that of Mahomet. He had preached his gospel. He had laid down the laws that were to be followed. Was not that enough? Why did he need a successor?
The explanation is that while Mahomet was a great preacher, or prophet, he also held a position of leadership over the Arabs which we have no one word to express. Perhaps it can be stated best by saying simply that the Arabs did what he told them to do. It also looks as if he was wise enough to tell them to do things that they were not likely to object to doing. I suppose we may state that he was a ruler with the limits of his authority not very clearly defined. But his influence was very powerful, because he gave out, and probably believed, that whatever he told the people was put into his mouth by Allah, the only God, whose prophet he claimed to be.
This "only God" was a phrase that was often repeated by the Mahommedans in opposition to the "Trinity" of the Christians, to whom the Deity was revealed as being "three Persons and one God."
The caliphs
Therefore, if Mahomet had died without a successor to an authority in some part like his own, the people would have been quite at a loss for a guide and ruler. He was in fact succeeded by "caliphs," as they were, and as they still are, called, the word caliph actually meaning "successor" or "representative." The caliphs were supposed to be "representative" of Mahomet, to succeed to some of his authority, rather as the Popes of Rome were deemed to succeed to and be representative of the authority of St. Peter. They did not pretend to receive messages from Allah, as Mahomet had received them, but they would uphold the teaching of Mahomet; and their explanations of doubtful points in his teaching were likely to be accepted by all Mahommedans. And although they were not held in the same honour as Mahomet, they were regarded as rulers of the nation whom all men should obey for the sake of their good fortune both in this world and in the next.
Now, in Syria and in Asia Minor generally, the population was probably far more nearly akin to the Arabians than to the Romans or the Greeks. It was from Arabia that the Semitic tribes had come into the country westward from the Euphrates and the Tigris and thence had spread over Syria and Palestine. The Saracens had little difficulty with them. The Persians had a stronger feeling of nationality and made more resistance, but before the middle of the seventh century Persia too was conquered.