The Decline and Fall of the Islamic Empire

Arriving at the horseshoe arch of the famed Alhambra Palace in Granada, Spain, in the summer of 1986, I felt disappointed. What is regarded as the finest example of Islamic architecture looked positively like a forbidding fortress.
I wasn't prepared though to see the stunning interior of the Hall of the Ambassadors. I gazed in wonder at the stalactite-like ceiling which simulated the vast expanse of the universe and the endless Arabic calligraphy of verses from the Qur'an on the wall. I eagerly took souvenir shots at the Court of Lions, probably the most famous courtyard in the world, and remembered the tales of the Alhambra written by Washington Irving.
The triumphant Spanish sovereigns, Ferdinand and Isabella, drove out the last sultan of Granada, Boabdil (Muhammad XI) in 1492, the year of the Reconquista and the same year Columbus discovered America for the Spanish crown. In the 10th century, the Andalucian city of Cordoba in Islamic Spain was not only the world's largest city but also the main center of learning. Muslim scholars translated and annotated for posterity the works of Socrates, Aristotle and Plato, among others, from Greek into Arabic. The Arab physician, Avicenna, was regarded as the foremost authority in medicine. Arab mathematicians introduced the numeral zero (zifr in Arabic) and pushed the frontier of science and technology.
What caused the decline and fall of the Islamic Empire? Harvard University Professor David Landes, in his book, "The Wealth and Poverty of Nations," argued that the cause was mainly due to the failure of Muslim rulers to foster an inquiring mind among their subjects. The state apparatus was dedicated solely to preserving the ruler's hold on power. Harun ar-Rashid, the celebrated caliph of Baghdad in the "Arabian Nights," asserting that the truth had been revealed in the Qur'an, decreed that all books be thrown into the Tigris River.
According to Professor Landes, history has demonstrated that the only way forward is to keep an open mind and avoid dogma. Mankind needed the Renaissance or the Age of Enlightenment to finally leave the Dark Ages and ignorance behind.