In A.D. 610, during the Islamic month of Ramadan, a 40-year-old merchant named Muhammad (570-632) was finding solace from the outside world in a cave not far from Mecca in what is now Saudi Arabia. This reputedly quiet, affectionate and kind man had been a caravan master. Now, married to a rich widow, his former employer, he had plenty of time for such solitude and reflection. By accounts he was worried about a moral crisis of reckless materialism hindering his Arabic society. Along with committing blatant idolatry, the poor and disadvantaged were in a serious state of neglect.

In the words of Karen Armstrong, Muhammad awoke one night "to find himself overpowered by a devastating presence, which squeezed him tightly until he heard the words of a new Arabic scripture pouring from his lips" (Islam: A Short History, 2000, pp. 3-4). He later understood that presence to be an angel. And, reportedly, it was through such means that the one God (Allah, the Arabic word for God)-the creator and sustainer of the world-and His will were revealed to the one whom more than a billion people now regard as "the Prophet."

After further experiences or visions of this type, Muhammad began preaching and gaining converts in 612. Apparently he did not think of founding a new religion but merely of bringing the revelation of Allah to the Arab world. He preached against the multitudinous gods and idols of the time. Muhammad became aware that the Arabs sprang from Ishmael (Ismail in Arabic), one of the sons of the biblical patriarch Abraham (or Ibrahim). We are told that he highly regarded the Old Testament prophets and Jesus of Nazareth, though he claimed that Jews and Christians had corrupted their sacred texts as passed down. Indeed, he saw himself as restoring the Abrahamic religion.

The religion Muhammad proclaimed eventually came to be named Islam, in essence meaning surrender to the will of God. Its adherents became known as Muslims (or Moslems); that is, those accepting this surrender.

Muhammad's disciples memorized his recitations. After his death they wrote them down to form the Koran (or Qur'an, meaning "reading"). According to Islamic thought, God's will is revealed to man through the Koran-the record of God's revelation to His messenger Muhammad. Muslims understand Muhammad to be the last of a long series of prophets, including Adam, Noah, Abraham, Moses and Jesus. Written in classic Arabic and 80 percent of the length of the New Testament, the Koran includes pronouncements against idolatry and mandates for social justice.

At first Muhammad made few converts. After four years of preaching, he had only about 70 followers. But he was undaunted, and soon many more were attracted to the new faith. Yet this religion brought drastic social repercussions with it. Because Muhammad's teachings threatened the religion and the commerce of the people of Mecca, they persecuted him and his growing band of believers, at last forcing him, in 622, to flee to the Arabian city later called Medina. His flight, called the Hegira (or Hijra), marks the beginning of the Islamic calendar.

Up to this point Muhammad had proclaimed a peaceful religion concerned with social justice and providing for the poor-and patience in the face of persecution. Yet, after his flight to Medina, things began to change. Gaining power, he announced that God had ordered Muslims to fight unbelievers. According to historian John Glubb: "The prophet, so patient, humble and devoted under persecution in Mecca, commenced to use power politics after his arrival in Medina. Not only does he resort to war against the Meccans, but in Medina he drives the Jews into exile and arranges for his opponents to be assassinated."

According to another history: "Toward the end of his life [Muhammad] was responsible for organizing several expeditions against the Christian Arab border states, on the north of the [Arabian] peninsula" (Geoffrey Parrinder, editor, World Religions: From Ancient History to the Present, 1983, p. 469). Whatever words he may have used, his example spoke volumes. Shortly after his death, in 632, the "sword of Islam" began conquering vast tracts of the known civilized world.

This was, as the Muslims understood it, jihad-holy war. Historically, jihad was not itself meant to convert individuals to Islam. Rather, its supporters understood it to gain political control of society and administer it through the principles of Islam. Conversions of individuals were to be a by-product of Muslim authorities taking over and imposing righteous laws. According to strict Muslim doctrine, compulsory conversions are forbidden. Yet that did not stop Arab warriors from demanding of pagans that they "accept Islam or die." In fact, it was mainly through that kind of missionary efforts that Islam spread.

Soon Islamic armies rampaged against the decadent Sassanid (Persian) and Byzantine (Asia Minor-Greek) forces controlling the Middle East, quickly defeating them. Arab warriors conquered Jerusalem in 638. By the early 700s Islam had spread across North Africa. It then pushed east as far as India and north as far as Spain. From there the Arab raiders attempted to conquer the rest of Europe but were stopped in 732 at the Battle of Tours in the plains of Poitiers, France, by the armies of the French prince, Charles Martel. Unable to spread further into Europe, Islam continued south and east, carrying its holy war into other parts of Africa, the Middle East, India and the rest of Asia.

American author Louis L'Amour , noted for his extensive research, summarized the spread of Islam as follows: "In the space of one hundred years following the death of Mohammed in 632, the Arabs had carried the sword of Islam from the Atlantic to the Indian Ocean, holding at one time most of Spain, part of southern France, the isle of Sicily, all of North Africa and Egypt, all of Arabia, the Holy Land, Armenia, Persia, Afghanistan, and almost a third of India. The empire of the Arabs was larger than that of Alexander the Great or of Rome" (The Walking Drum, 1984, p. 171).

It is important to realize that Jews and Christians, whose religious traditions Muhammad saw himself as succeeding, were accorded special favor in this conquest. He allowed them to keep their religion as long as they paid a tax. In this respect the Islamic empire was more tolerant of Jews and Christians than Christian Europe was of Jews and Muslims during much of its history. Muslims gave those who were not Jews or Christians the simple choice of converting to Islam or death.

Yet, as L'Amour writes: "They came with the sword, but they retained the best of what they discovered. Much that we know of Arab science was born from the minds of Jews, Persians, Greeks, various Central Asiatic peoples, and the Berbers, but it flowered under Arab enthusiasm. A scholar was welcome everywhere ... [and] for more than five hundred years the Arabs carried the torch of civilization" (pp. 171-172).

While Europe languished in the poverty and ignorance of the Dark Ages, the Arabs were developing libraries and learning centers. They preserved the great works of ancient Greece and Rome, transmitting to us the decimal system, logarithms, algebra and trigonometry. Under their patronage, medical treatment, botany, geography, zoology and other studies advanced.

Over the centuries Islam spread throughout the Arab world, ultimately becoming one of the world's great religions. Though often violent, expansion has been peaceful at times-as Muslim populations simply expanded and overflowed into other areas. In its tumultuous history, genuine missionary activity has ebbed and flowed, experiencing a sharp increase in the 20th century.

As noted earlier, Islam has more than a billion adherents. They live in every country. Indeed, although most Arabs are Muslim, no longer are most Muslims Arab. About one third of Africa is Muslim. Even America has seen peaceful Islamic growth. Time reported that Islam may be America's fastest-growing religion. "The country's 7 million Muslims are overwhelmingly middle and professional class" (Atlantic edition, Sept. 24, 2001). GN