At the age of 40, while engaged in a meditative retreat, Muhammad peace be upon him received his first revelation from Allah through the Angel Gabriel. This revelation, which continued for twenty-three years, is known as the Quran.

As soon as he began to recite the words he heard from Gabriel, and to preach the truth which Allah had revealed to him, he and his small group of followers suffered bitter persecution, which grew so fierce that in the year 622 Allah gave them the command to emigrate. This event, the Hijra, 'migration', in which they left Makkah for the city of Madinah some 260 miles to the north, marks the beginning of the Muslim calendar.

After several years, the Prophet peace be upon him and his followers were able to return to Makkah, where they forgave their enemies and established Islam definitively. Before the Prophet peace be upon him died at the age of 63, the greater part of Arabia was Muslim, and within a century of his death Islam had spread to Spain in the West and as far East as China.

How did the spread of Islam affect the world?

Among the reasons for the rapid and peaceful spread of Islam was the simplicity of its doctrine - Islam calls for faith in only One Allah worthy of worship. It also repeatedly instructs man to use his powers of intelligence and observation.

Within a few years, great civilizations and universities were flourishing, for according to the Prophet peace be upon him, 'seeking knowledge is an obligation for every Muslim man and woman'. The synthesis of Eastern and Western ideas and of new thought with old, brought about great advances in medicine, mathematics, physics, astronomy, geography, architecture, art, literature, and history. Many crucial systems such as algebra, the Arabic numerals, and also the concept of the zero (vital to the advancement of mathematics), were transmitted to medieval Europe from Islam. Sophisticated instruments which were to make possible the European voyages of discovery were developed, including the astrolabe, the quadrant and good navigational maps.