Islam instructs man to use his powers of intelligence and observation. Within a few years of the spread of Islam, great civilizations and universities were flourishing. 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 the concept of zero (vital to the advancement of mathematics), were transmitted to medieval Europe from the Muslim world. Sophisticated instruments which were to make possible the European voyages of discovery, such as the astrolabe, the quadrant, and good navigational maps, were also developed by Muslims.