Prince Henry, the So-Called Navigator

I’ve been thinking about Prince Henry the Navigator of Portugal today, and re-reading bits of Peter Russell’s excellent biography,  Prince Henry “the Navigator”: A Life

You remember Prince Henry.  He’s the first in a series of names that you learned in grade school:  Prince Henry the Navigator, Columbus, Dias, Magellan–maybe Henry Hudson if your teacher was into the Great Explorers and the Age of Discovery.

If you got hooked, you trotted down to the school library and checked out a biography–or three.  (Not that I admit to having done anything of the sort.)  They introduced you to the princely scholar who founded a school on the coast of Portugal where he taught new arts of navigation to his sailors.  The visionary who sent men out explore the cost of Africa with the goal of reaching India.  The gifted mathematician whose theories made oceanic navigation possible.  The dynamic symbol of Portugal’s imperial destiny.  In short, a heroic figure a nerd could love.

Not surprisingly, the story told in a biography suitable for a ten-year-old is little more than a series of half-truths.  Even the nickname “the Navigator” is a misnomer, invented by nineteenth century historians eager to establish the Portuguese grandson of John of Gaunt as the forefather of British maritime success.  In fact, the prince’s only personal experience of seafaring was trips along the Portuguese post and the occasional short hop to Morocco.

Henry was an ambitious prince, a would-be Crusader, a celibate Christian knight, a talented administrator, and a shrewd businessman.  For more than forty years he funded expeditions of exploration along the west coast of Africa, pushing Portuguese seamen to sail further than they ever had before.  By providing the financial support and intellectual stimulus for Portugal’s voyages of discovery, Prince Henry the Navigator transformed Portugal from a small, impoverished nation into Europe’s first maritime empire.  Now that I think about it, a hero that a grown-up nerd can still admire.

Go, Henry.

Al-Khwarizmi Does the Math

Quick:  multiply DVII by XVIII.  Before you could work the problem you translated it into Arabic numbers didn’t you?

The person you can thank, or blame, for your ability to multiply and divide is the mathematician and astronomer Muhammad ibn Musa al-Khwarizmi (ca. 783-847), whose name lives on in a mangled form as “algorithm.  (Honest.  Take a moment to sound it out.)

We know very little about al-Kwarizmi’s life.  His name suggests he was born in the region of Khwarazm in what is now Uzbekistan.  There are suggestions that he was a Zoroastrian, who may have converted to Islam.

We know a lot about al-Kwarizmi’s work as a scholar in al-Mansur’s court in Baghdad.  He introduced what were then called “Hindu numerals” to the Muslim world.  He produced an important astronomical chart (zij) that made it possible to calculate the positions of the sun, the moon and the major planets and to tell time based on stellar and solar observations.

Al-Kwarizmi’s most important contribution to science was a ground-breaking mathematical treatise: al-Kitab al-Mukhtasar fi Hisab al-Jebr wal-Muqabala. The title translates to The Compendium on Calculation by Restoration and Balancing, but the book is most often referred to as al-jebr, or algebra.  His treatise was a combination of mathematical theory and practical examples related to inheritances, property division, land measurements, and canal digging.  He was the inventor both of quadratic equations and the dreaded word problem.    (Some of his word problems became classics, which meant they were still giving schoolboys grief several centuries later.)

So, the next time you need to calculate how long it will take for two cars to meet in Dubuque if one car leaves Minneapolis going 60 miles an hour and the other leaves Peoria traveling 75 miles an hour?  Thank al-Khwarizmi.

This post previously appeared in Wonders & Marvels.


Building Baghdad

Today we think of Baghdad in terms of tyranny, terrorism and mistakes. A sinkhole for American troops.  A sandbox for suicide bombers.

In the eighth century, Baghdad was the largest city in the world–and the most exciting.  Like Paris in the 1890s, Baghdad was a cultural magnet that drew scientists, poets, scholars and artists from all over the civilized world.  (Just for the record, that didn’t include Europe, which was having a bit of trouble on the civilization front in the centuries after the fall of Rome.)

Baghdad was a brand new city, built to replace Damascus as the capital of an Islamic empire that was no longer the sole property of the Arab tribes. The Abbasid caliph al-Mansur had his architects draw the outer walls of his new capital in a perfect circle, using the geometric precepts of Euclid.

Completed in 765, the Round City grew quickly. Within fifty years, it had a population of more than a million people: Muslim and Christian Arabs, non-Arab Muslims, Jews, Zoroastrians, Sabians and an occasional Hindu scholar visiting from India.  It had separate districts for different trades, including a street devoted to booksellers and papermakers.

Most important of all, Baghdad had libraries. Encouraged by an official policy of intellectual curiosity, scholars in Baghdad collected works of literature, philosophy and science from all corners of the empire.  (Baghdad reportedly negotiated for a copy of Ptolemy’s Megale Syntax as part of a peace treaty with Byzantium.) Ambitious nobles followed the caliphs’ example and created their own libraries, many of which were open to scholars. Working in a culture that encouraged learning, Abbasid scholars in the eighth through the tenth centuries not only transcribed and translated the classical scholarship of Greece, Persia and India, they transformed it, pushing the boundaries of knowledge forward in mathematics, geography, astronomy and medicine.

This post previously appeared in Wonders & Marvels

(Dear Readers:  I’ve been AWOL for a few weeks because I’m working on a big exciting project that I can’t tell you about just yet.  It finally dawned on me that I have some posts and articles from other places that you might enjoy. Sometimes I’m a bit slow.  Thanks for sticking with me.–Pamela.)