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 (SAW) '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.
The Prophet (SAW) said, 'Seek knowledge even into China': the Hui Shen mosque was built in the seventh century.