Among the reasons for the rapid and peaceful spread of Islam was the simplicity of its doctrine - Islam calls for faith in only one God 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, '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.
Unlike Christianity where religion and science are two separate elements, the study of science has always been compatible with Islam. The Islamic ability to reconcile monotheism and science proves to be the first time in human thought that theology, philosophy, and science were finally harmonized in a unified whole. Thus the magnitude of their pioneering contributions were enormous, considering its effect upon scientific and philosophic thought and upon the theology of later times.
The Islamic empires, in the early 6th centuries, were the inheritors of the scientific tradition of late antiquity. They preserved it, elaborated it, and finally, passed it to Europe. This time period, which was Europe's dark ages, were, for Muslim scholars, a time of philosophical and scientific discovery and development. The Arabs at the time not only assimilated the ancient wisdom of Persia, and the classical heritage of Greece, but adapted their own distinctive needs and ways of thinking. Muslim scholars studied the ancient civilizations from Greece and Rome to China and India. The works of Aristotle, Ptolemy, Euclid and others were translated into Arabic. Muslim scholars and scientists then added their own creative ideas, discoveries and inventions, and finally transmitted this new knowledge to Europe, leading directly to the Renaissance. Many scientific and medical treatises, having been translated into Latin, were standard text and reference books as late as the 17th and 18th centuries in Europe.
Within a few years, great civilizations and universities were flourishing, for according to the Prophet, 'seeking knowledge is an obligation for every Muslim man and woman'. The outcome is shown in the spread of Islamic universities; Al-Zaytunah in Tunisia, and Al-Azhar in Cairo go back more than 1000 years and are the oldest existing universities in the world. Indeed, they were the models for the first European universities, such as Bologna, Heidelberg, and the Sorbonne. Even the familiar academic cap and gown originated at Al-Azhar University. 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.
During the period in Spain (known to the Muslims as Andalus), it was the golden age of Islam whereas Europe was steeped in the dark ages. Within two hundred years the Muslims had turned Andalus into a bastion of culture, commerce and beauty. Irrigation systems imported from Syria and Arabia turned the dry plains into an agricultural cornucopia. Olives and wheat had always grown there. The Arabs added pomegranates, oranges, lemons, aubergines, artichokes, cumin, coriander, bananas, almonds, henna, woad, madder, saffron, sugar-cane, cotton, rice, figs, grapes, peaches, apricots and rice. It became the intellectual centre of Europe There was nothing like it, at that epoch, in the rest of Europe. The best minds in that continent looked to Spain for everything.