From Mecca to Toledo
1Islam began in Arabia in the early 600s. Muslims believe that, starting about 610, God's revelations came to Muhammad, a merchant of Mecca, through the angel Gabriel. These revelations were later gathered into the Quran. In 622 Muhammad and his followers moved to the city of Medina. That journey, the hijra, marks the first year of the Islamic calendar. By the time Muhammad died in 632, much of Arabia had accepted Islam.
2The caliphs, the leaders who came after Muhammad, sent Arab armies north and west. Within about twenty years they had won Syria, Egypt and Persia. The Umayyad caliphs ruled from Damascus beginning in 661, and in 711 their forces crossed into Spain and also reached the Indus River. Many conquered peoples kept their own religions for a time and paid a special tax, and conversion often happened slowly over generations. A disagreement over who should lead the community split Muslims into Sunni and Shia branches.
3In 750 a new family, the Abbasids, took power, and in 762 they founded Baghdad. Arabic became a shared language of learning across a huge area, and paper, a skill learned from China, made books cheaper to copy. In Baghdad's House of Wisdom, scholars translated Greek, Persian and Indian works into Arabic and added discoveries of their own. Al-Khwarizmi wrote a book on al-jabr, which gave us the word algebra, and explained the Indian number system with zero. The doctor al-Razi described how to tell smallpox from measles, and large cities had hospitals. Ibn al-Haytham tested ideas about light with careful experiments, and astronomers improved the astrolabe.
4Merchants spread both goods and faith. Muslim traders sailed the Indian Ocean and crossed the Sahara, and Islam reached West Africa and Southeast Asia mostly through them. Merchants used written orders to pay, called sakk, so they did not have to carry as much coin. Each year the hajj brought pilgrims from many lands to Mecca.
5Muslim rulers governed much of Spain, called al-Andalus, for centuries, and Córdoba grew into one of Europe's largest cities. In 1085 the Christian king of Castile captured Toledo, a city whose libraries held many Arabic books. During the 1100s, scholars from across Europe traveled to Toledo. Working with Jewish, Christian and Muslim helpers who knew Arabic, they turned Arabic books into Latin, the language of learning in Europe.