For a brief moment, towards the end of the 12th century, the Muslim world was politically united under one caliph ruling from Baghdad. This political unity, rare in Islamic history, projected itself on the military plane. In West Asia, the Crusaders were ejected from Palestine, Lebanon and Syria. Salahuddin recaptured Jerusalem in 1187. Four years later, in 1191, Muhammed Ghori of Ghazna...

Abu al-Qasim Khalaf ibn al-Abbas Al-Zahrawi was born near Cordoba, Spain, when it was part of the Islamic Empire. He was a physician, surgeon and chemist. He is best remembered for his encyclopedia of medicine, the Al-Tasrif li man ajaz an-il-talif (An Aid for Those Who Lack the Capacity to Read Big Books), known as the al-Tasrif. This became a standard reference in Islamic and European...