The Islamic empire began to expand beyond the Arabian Peninsula after the death of the prophet and founder of Islam, Mohammed, in 632 AD. Islamic leaders conquered Iran in 641 and in 642 Egypt was under Islamic control. In the eighth century, all of northern Africa, the Iberian Peninsula (Spain and Portugal), India and Indonesia became Islamic lands. The Muslims were stopped at France by their defeat at the Battle of Tours in 732. Nonetheless, Islamic rule continued on the Iberian Peninsula for nearly nine centuries.
Around 762, Baghdad became the intellectual capital of the empire and issued a request for books from throughout the world. Traders were given the weight of the book in gold. Over time, Baghdad accumulated a wealth of knowledge and many key geographical works from the Greeks and Romans. Ptolemy's Almagest, which was a reference to the location and movement of heavenly bodies along with his Geography, a description of the world and a gazetteer of places, were two of the first books translated, thus keeping their information in existence. With their extensive libraries, the Islamic view of the world between 800 and 1400 was much more accurate than the Christian view of the world.
The Muslims were natural explorers since the Koran (the first book written in Arabic) mandated a pilgrimage (hajj) to Mecca for every able-bodied male at least once in their life. With thousands traveling from the farthest reaches of the Islamic Empire to Mecca, dozens of travel guides were written to assist in the trip. Pilgrimage during the seventh to tenth month of the Islamic calendar each year led to further exploration beyond the Arabian Peninsula. By the eleventh century, Islamic traders had explored the eastern coast of Africa to 20 degrees south of the Equator (near contemporary Mozambique).
Islamic geography was primarily a continuation of the Greek and Roman scholarship which had been lost in Christian Europe. There were some additions to the collective knowledge by their geographers, especially Al-Idrisi, Ibn-Batuta, and Ibn-Khaldun.
Al-Idrisi (also transliterated as Edrisi, 1099-1166 or 1180) served King Roger II of Sicily. He worked for the king in Palermo and wrote a geography of the world called Amusement for Him Who Desires to Travel Around the World which wasn't translated into Latin until 1619. He determined the circumference of the earth to be about 23,000 miles (it is actually 24,901.55 miles).
Ibn-Batuta (1304-1369 or 1377) is known as the "Muslim Marco Polo." In 1325 he traveled to Mecca for a pilgrimage and while there decided to devote his life to travel. Among other places, he visited Africa, Russia, India, and China. He served the Chinese Emperor, the Mongol Emperor, and the Islamic Sultan in a variety of diplomatic positions. During his life, he traveled approximately 75,000 miles, which at the time was farther than anyone else in the world had traveled. He dictated a book which was an encyclopedia of Islamic practices around the world.
Ibn-Khaldun (1332-1406) wrote a comprehensive world history and geography. He discussed the effects of the environment on humans so he is known as one of the first environmental determinists. He felt that the northern and southern extremes of the earth were the least civilized.
By translating important Greek and Roman texts and by contributing to the knowledge of the world, Islamic scholars helped provide the information which allowed the discovery and exploration of the New World in the fifteenth and sixteenth centuries.