Fibonacci

While the foundation of the Tower of Pisa was being being laid, a man was born nearby who developed math skills that might have helped the ill-fated architectural wonder.
Leonardo Pisano ("of Pisa") (c.1175-c.1250) was the son of Guglielmo Bonacci. Although known as "Leonardo Pisano" during his lietime, he signed his name "Bonacci" on his writings; an 1838 writer referred to him as "Fibonacci"—short for filius Bonacci ("son of Bonacci")—and the name stuck with his modern fans.

His father was a customs officer in Algeria, and between living there and traveling around the coast of the Mediterranean, Leonardo grew up exposed to education outside of the Greco-Roman/Western European tradition. He recognized the advantages of the Hindu-Arabic system of numbers over using Roman numerals, and worked to popularize it in Europe, starting with his 1202 work Liber Abaci ("Book of the Abacus" or "Book of Calculating"). In it, he presented to Europe the decimal system by which we all learn the four basic mathematical functions in school.

Calculating with the four functions in a decimal system.

The decimal system, with its "places" for ones and tens and hundreds, etc.,  was much "neater" than the system of Roman numerals and included a digit for "zero." Roman numerals had no "zero," and the words null or nihil were used to express a lack of something. The Roman tradition had great difficulty with the concept of "nothing" in math, because it seemed inappropriate to have a "something" that would indicate a "nothing."

If people have heard of Fibonacci in the present day, it is usually because of a particular sequence of numbers associated with him. In Chapter 12 of the Liber Abaci, he presents a math problem: how many rabbits are created in one year starting with one pair? After describing the progression in words, he shows the number progression as 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. Examples of this series existed prior to Fibonnaci, and it is likely that he was simply repeating something he had learned, but 19th century mathematician Edouard Lucas called this sequence the Fibonacci numbers. They have been found to relate to many phenomena found in nature. (A thorough discussion is impossible here, but look.)

A webpage with some simple representations of the Fibonacci sequence is here.

The First Female Professor of Medicine

The medical school in Salerno had on its staff the first well-known female physician and professor of medicine. Sadly, we know nothing of her personal life, not even her dates: her existence at Salerno in the 11th or 12th centuries is inferred from the handful of texts she wrote or contributed to. Fortunately, her texts were considered important enough that they were preserved and copied, translated and distributed throughout Europe.

Trotula

Her name was Trotula (listen here for pronunciation), and we find it on several texts. The best-known is the three works collectively known as La Trotula.

• Conditions of Women—based on the Latin translation of an Arabic work, with additions of several Latin-based passages that had been around for awhile.
• Treatments for Women—"a disorganized collection of empirical cures with only a thin theoretical overlay."*
• Women's Cosmetics—a head-to-toe listing of ways to beautify all aspects of a woman's appearance, with no medicinal applications.

Although there are conditions that make no sense to modern medicine (such as a "wandering womb"), there are also techniques that we would consider very sound, such as using opium on the patient during childbirth (defying church tradition that women should suffer; see Genesis 3:16), and using silk thread to repair tears that occur in childbirth.

Some scholars have attributed these works to a man, perhaps through simple chauvinism, but also because it is believed that the frank addressing of gynecological topics would be too indelicate for a female author of the era. The author of La Trotula, however, self-identifies in the texts as a woman, and the analysis of history is always turning up surprises that challenge modern notions of medieval sensibilities. Also, in Chaucer's Canterbury Tales, the book of wicked wives read by the Wife's husband Jankyn includes the name "Trotula." However little we may know of her now, it seems she developed a reputation that preserved her name for at least a couple centuries after her prime.

*Quotation from The Trotula: An English Translation of the Medieval Compendium of Women's Medicine, by Monica Green.

The Edict of Salerno

Salerno, located on the lower "shin" of Italy's southwest coast, has been occupied continuously since pre-historic times, frequently changing hands due to the many wars in the peninsula. Despite the changing political landscape, however, at least one feature of Salerno rose to a prominence that it held for several centuries, through several political shifts.

We don't know precisely when the Schola Medica Salernitana (Medical School of Salerno) was founded, but at some point, the dispensary of a 9th century monastery became a focal point for medical study and earned the title of the first medical school in history. Because of the fame of the school, Salerno became known as the "Town of Hippocrates."

The School today.

One of its unique qualities for the time was that it not only was well-versed in the Greco-Roman traditions of Hippocrates, Galen, Dioscorides and others. Its proximity to North Africa and Sicily gave it access to Arabic learning (Sicily was under Arab control from 956 until 1072). In fact, it was the arrival in 1077 of the Tunisian Muslim merchant-turned-monk Constantinus Africanus that started a Golden Age at the school. He compiled the Liber Pantegni (Book of All Arts).  It was (as is typical for the time) largely a collection of the work of others, but it drew together Greek and Arabic medical knowledge in what is called the earliest surviving Western medical treatise [source].

Salerno produced other medical texts as well. A 12th century pair named Johannes and Matthaeus Plantearius wrote the Liber de Simplici Medicina (Book of Simple Medicine). Several books on gynecology and cosmetics were created by the most famous woman doctor of the time.

Salerno thrived, even after Holy Roman Emperor Frederick II declared the Edict of Salerno. The Modern Age would approve of the Edict: it created a legal separation between physicians and apothecaries. Physicians could no longer prescribe medicines that they themselves prepared and sold. The Edict also fixed prices to prevent overcharging the sick. Over time, this Edict was copied throughout Europe, and we have reason to be glad that similar regulations exist today.

The Two Kings Henry

Henry, the young king.

For a time, the Capetian Dynasty in France had the habit of naming and actually crowning the king's heir in the old king's lifetime. King Stephen and King Henry II of England adopted this policy. In June 1170, King Henry II crowned his 15-year-old son Henry. Watching the ceremony would have been the 13-year-old Richard (later King and Lionheart), 12-year-old Geoffrey, and 3-year-old John (later "Bad King John").

"Young King Henry" (1155-1183) was considered handsome, charming, and popular; however, he showed no apparent skill or interest in politics, military skill, or even ordinary intelligence. For these reasons, it is probably good that his father never entrusted him with any authority. In fact, Henry II seems to have used his son as a political tool.

• Henry was betrothed to Margaret, daughter of Louis VII of France, on the condition that her dowry would be the Vexin, the border region between the England-held Normandy and France itself. (A nice expansion of England's property on the continent.)
• Because Pope Alexander III needed help dealing with Frederick I, Holy Roman Emperor, he acquiesced to Henry's request to allow the children to be married in 1160, giving England the Vexin. (There was no ceremony until 1172.)
• Henry had the royal wedding officiated by the Archbishop of York instead of the Archbishop of Canterbury, as was customary. This was likely an attempt to put the Archbishop of Canterbury, Thomas Beckett, in his place. (He would be dead six months later.)

The benefit of naming your heir early was to avoid disputes at the senior king's death over the succession. In this case, however, since young Henry would inherit vast lands with the throne, he was given a house and staff and large income—and even one of the most respected men of the age, William Marshal, as a tutor in arms—but not provinces and territories like his younger brothers. Consequently, his brothers had more power than he. This would have rankled the young king while his father lived on...and on.*

In 1173, Henry the young king led a rebellion with his brothers, his mother,  the kings of France and Scotland, the Count of Flanders, et alia, against his father (this really was the most turbulent family in the Middle Ages). The same qualities and actions that brought Henry II rivals and enemies, however, also brought him great wealth, and he was able to hire sufficient mercenary forces to put down what was later called the Great Rebellion. (It was the English opposition to all the foreign mercenaries on England's soil that prompted Henry to create the Assize of Arms.)

Young Henry rebelled again in 1183 against his father and his brother, Richard, over Richard's iron-fisted rule of the Duchy of Aquitaine. Henry had the help of his brother Geoffrey and Aquitaine locals who were willing to throw off Richard's rule, but the sudden death of the young king on June 11, 1183, ended the attempt. He was a little over 28 years old. King Philip of France, the brother of Margaret, lost little time in asking for the return of her dowry, the Vexin.** Instead of the land, France accepted an annual payment from Henry II.

Because he never ruled, he is not counted in the list of Kings of England. He is neglected by history in favor of his younger brothers, but he is not without fans: a recent website is devoted to him.


*Queen Elizabeth should be glad that the House of Windsor does not appear to have any of the Plantagenet temper.
**The 1967 movie The Lion in Winter is a highly fictionalized—and highly entertaining—account of this meeting.

Roger of Hoveden

One of the men who went on the Third Crusade (talked about here and here), wrote accounts of some of the events of that adventure, notably The Fall of Jerusalem, 1187 and Laws of Richard I (Coeur de Lion) Concerning Crusaders Who Were to Go by Sea. He didn't witness the Fall of Jerusalem himself, however, having gone over with Richard I in August 1190 and returning to Europe in August 1191 with Phillip II of France.

Roger of Hoveden (d.1201?) was unknown to history until 1174, when Henry II sent him on a secret mission to the lords of Galloway in southwest Scotland. His name suggests he was born in what is now called Howden, in Yorkshire. His death date is inferred from the fact that one of his historical works, called the Chronica, breaks off suddenly at 1201.

The Chronica (Chronicles) is an attempt (like the Anglo-Saxon Chronicle) to create a comprehensive history of England. For the parts of English history preceding his own life, he mostly just copies earlier works. From 732-1170, he uses other works. From 1170-1192, he copies his own earlier work, the Gesta Henrici II et Gesta Regis Ricardi (Works of Henry II and Works of King Richard).* The Gesta is the best evidence that Hoveden must have been well-connected at Henry's court: he shows detailed knowledge of political events, and is more sympathetic to Henry's side in the ongoing disputes between Henry and his sons and others. From 1192 until its abrupt end in 1201, the Chronica (along with the Gesta) is a valuable tool for understanding some of the changes in England's constitutional development.

Here is an excerpt from the Chronica for 1183, with what might seem an interesting puzzle:

In the year of grace 1183, being the twenty-ninth year of the reign of king Henry, son of the empress Matilda, the said king of England was at Caen, in Normandy, on the day of the Nativity of our Lord; the king also, and Richard and Geoffrey, ... . After the Nativity of our Lord, the king ordered the king, his son, to receive homage from Richard, earl of Poitou, and from Geoffrey, earl of Brittany, his brothers; on which, in obedience to his father, he received the homage of his brother Geoffrey, and was willing to receive it from his brother Richard, but Richard refused to do homage to him; and afterwards, when Richard offered to do homage to him, the king, the son, refused to receive it. Richard, feeling greatly indignant at this, withdrew from the court of the king, his father, and going to Poitou, his own territory, built there some new castles and fortified the old ones.

Does it seem to you that there are two kings mentioned here? There are. Tomorrow we'll look at when England had two Kings Henry at the same time.

*This work was originally attributed to Abbot Benedict of Peterborough, because his name appeared on a copy in Benedict's library. Benedict's library-building habits are well-known, however, and evidence exists that he had a copy of the Gesta made from its original source.

From Scroll to Book

DailyMedieval has mentioned books several times, and it occurs to me that people might be asking themselves "When he says book does he mean scroll? When did the switch to binding flat pages take place?"

Surprisingly early, as it happens. The earliest examples of bookbinding are from India before the Common Era, where a sutra (from the word for "a rope or thread that holds things together") was made from palm leaves, written on, then sewn together along one edge; enclosed in wooden boards, the excess thread was wound around the boards to keep all together. Buddhist monks carried this technique through Persia, Afghanistan, Iran, until it reached China in the 1st century BCE.

This method spread slowly, but by the 4th century CE bound books and scrolls were being produced in equal numbers (based on surviving texts). Using wooden boards to contain information was not a new idea. Wax tablets in a wooden frame existed from Roman times right through the Middle Ages (as mentioned here). The word "book," however, was not being used the way we use it today. Isidore of Seville (c.560-636), the famous early etymologist, said:

A codex is composed of many books; a book is of one scroll. It is called codex by way of metaphor from the trunks (codex) of trees or vines, as if it were a wooden stock, because it contains in itself a multitude of books, as it were of branches.

As for the word "book" itself, which eventually replaced the word "codex," its likeliest origin is in the word for beech. This has led scholars to assume that some of the earliest collections of writing (that weren't on scrolls) were written on beech wood.

The important point is that the development of the codex method of holding data increased the longevity of "books" over scrolls, which did not have hard covers and which experienced wear every time they were unrolled and re-rolled. "Books" could now be made larger, as well, without falling apart; meaning, for example, an entire Bible could be contained in one printed object.

Were there differing opinions on the usefulness or appropriateness of the different styles of "book"? Perhaps there were, although any difficulties in adapting to the new style probably did not go like this.

The Groma

[We had so much fun with the Jacob's Staff (well, I did), that I hope you don't mind talking so soon about another tool for more measurement.]

Roman roads, the grid system for Roman camps, sections of Hadrian's Wall—how did they get their lines so straight? They used a groma. The groma had several parts:

• The Upright: a long pole with a metal point on the bottom for driving it into the ground.
• The Rostro: an arm that extended horizontally from the top, then angled upward, designed to swivel where it attached to the Upright.
• The Groma: a cross of four equal-length arms, with its center at the top-point of the Rostro. From the end of each arm, an equal length plumb line descended.
• The Marker Peg: a plumb line that descended from the center of the Groma's cross-piece all the way to the ground.

The Upright would be stationed so that the Marker Peg fell to what you wished to be the center of your surveying. From there, you could swivel the Rostro so that each arm extended to the cardinal points of the compass. Once the four plumb lines ceased swaying, you could send your assistant toward the horizon (standard distance was 125 paces). By getting behind the groma and sighting so that two opposite plumb lines were aligned, you could, with a wave of your hand, guide your pole-carrying assistant laterally until his vertical pole aligned with the plumb lines. You now had a straight line of hundreds of feet between two points, exactly along the direction you wanted.

Who used the groma? Land surveyors, or as they were called in Latin, Agrimensores (from ager, "field" and mensura, "measure). Which brings me to the Corpus Agrimensorum Romanorum ("The Work of Roman Surveyors"), considered the earliest scientific or technical manuscript that exists, from a time (the 5th-6th centuries) when most documents were about religion or literature (or politics). The page seen here is from the section on laying out a house as opposed to a settlement. One picture is of the house, and one is of the property lines around it.

A 1554 edition of the Corpus added illustrations to the text with grid-lines to show the accuracy of the process. A few examples of its pages and illustrations can be seen here. And if you are interested in robots, you might get a chuckle from this after today's post.

Anglo-Saxon Chronicle

The Anglo-Saxon Chronicle has been mentioned here. King Alfred the Great (849-899) originally ordered its creation around 890 for a record of important events since the birth of Christ; it was maintained by anonymous scribes until the end of the reign of King Stephen in 1154. The original language is Anglo-Saxon, also known as Old English, a language all but unrecognizable to speakers of Modern English. By the 12th century, the vocabulary of entries was shifting to early Middle English. No single original manuscript exists. Of the nine fragments known, seven were found in the Cotton Library (see the above link), although the best version is in the Parker Chronicle at Corpus Christi College, Cambridge. The fragments have differences; some are surely scribal errors, some are definitely attempts by the copyist to "correct" or "amend" what they were copying with their own knowledge/beliefs.

It is, of course, historically highly inaccurate. The scribes were working with the best knowledge they had at the time, and motives ascribed to important political figures are suspect. Here is the opening, (collated from different manuscripts):

The island Britain is 800 miles long, and 200 miles broad. And there are in the island five nations; English, Welsh (or British), Scottish, Pictish, and Latin. The first inhabitants were the Britons, who came from Armenia, and first peopled Britain southward. Then happened it, that the Picts came south from Scythia, with long ships, not many; and, landing first in the northern part of Ireland, they told the Scots that they must dwell there. But they would not give them leave; for the Scots told them that they could not all dwell there together; "But," said the Scots, "we can nevertheless give you advice. We know another island here to the east. There you may dwell, if you will; and whosoever withstands you, we will assist you, that you may gain it." Then went the Picts and entered this land northward. Southward the Britons possessed it, as we before said. And the Picts obtained wives of the Scots, on condition that they chose their kings always on the female side; which they have continued to do, so long since. And it happened, in the run of years, that some party of Scots went from Ireland into Britain, and acquired some portion of this land. Their leader was called Reoda, from whom they are named Dalreodi.

For all its flaws, its nearly 100,000 words are, in many cases, the only human viewpoint we have on certain centuries. Also, its status in literature is assured as "the first continuous history written by Europeans in their own language."

The Assize of Arms

In the early Middle Ages, Britain was a collection of territories, each with its own leader(s), which formed a loose confederacy at times of national trouble. When William of Normandy conquered in 1066, he put the whole land under one rule, maintained by his lieutenants and supporters in positions of authority over chunks of real estate. This was the start of the feudal system.

While the king might keep troops near him, there was for a long time no standing army that could be applied immediately to a military conflict. In the 11th and 12th centuries, countries in Western Europe still relied on raising armies by calling for volunteers and paying men to fight. Often these men came from other lands. After Henry II had to put down a 1373-4 rebellion by bringing in Brabançon soldiers, and seeing the distrust of his English subjects for their presence—not to mention their dislike of the extra taxes required to pay for the king's mercenaries—he created the Assize of Arms in 1181.

The purpose of the Assize was to make certain there would be sufficient local military support for a campaign. It outlined the responsibilities of his subjects to have the proper arms and armor and to bring them when called upon. Some of its 12 provisions were:

1. Each knight must have a hauberk (armor covering at least neck and shoulders), helmet, shield and lance.
2. Each freeman (worth at least 16 marks) must have hauberk, helmet, shield and lance. Each freeman of 10 marks worth must have a light hauberk, iron cap and lance.
4. Every man must swear an oath that they will have these arms and carry them for King Henry.
5. If you die, your arms go to your son; if he is too young, his guardian must use them or find a suitable person until the son comes of age.
7. No Jew should have arms, but should sell them to someone who can use them in the king's service.
8. No one may sell, trade, or carry away these arms so that they leave England.
10. If any man does not have arms in accordance with this order, the king shall take not only his goods and land, but also his life and limbs.

The Assize enabled Henry II and his successors to save themselves the cost of maintaining a standing army. Moreover, an army could be called up and assembled within a matter of days with requiring extraordinary taxation. It was very useful for King Henry two years later, when he had to go to war against a rebellion by his son and heir, King Henry.

But that's a story for another day.

Before Marco, There was William

Everyone's heard of Marco Polo (1254-1324) and his travels with his Venetian uncles to the Far East. He was not alone, however, in leaving Europe on long journeys to strange lands.

The most detailed early account of life in Asia was written by a Flemish Franciscan monk named William Rubruck (Willem van Ruysbroeck, c.1210-1270). While on crusade with King Louis IX of France, in Palestine he met a Dominican sent by the pope to enlist the Mongols' aid against the Muslims. Rubruck decided he would try to convert the Mongols to Christianity.

Rubruck's Travels

He set out in 1253 on a round-trip journey that took him three years, traveling as far as the Mongol capital of Karakoram; he was the first European ever to visit it—that is, who also returned to write about it. His personal mission gave him the opportunity to write about what he saw and the ethnicities and religions and customs he observed.

It is interesting that, as he traveled, he often found other Europeans who recognized his Order because of his clothing. He was also questioned frequently about his "version" of Christianity. He met several Christians and Christian priests who were Nestorians. Nestorius (386-451) was a patriarch of Constantinople who claimed Jesus had two distinct natures: a human nature and a completely divine nature, referred to as Logos. These two natures, or essences, are connected but unmingled. When Nestorianism was condemned in 431 at the Council of Ephesus, the Assyrian Church refused to change their support for it. Rubruck had his work cut out for him: preaching Christianity, and preaching against the local Christianity.

There's more to say about Rubruck, but I'll leave off for today with a simple thought: if he had become more famous than the other guy, would there be a game now where people called out "William!" "Rubruck!"

Richard II's Feast

In 1390, King Richard II of England had his master chefs assemble a book of all their best recipes. This Forme of Cury (Forms of Cooking) was interesting enough that an edition was presented to Queen Elizabeth I. In 1975, Lorna J. Sass took the edition printed for the Early English Text Society* recipes and not only translated the recipes into Modern English (to the best of her understanding, given the imprecision of the directions), but also tested the recipes to determine proportions of ingredients that would result in dishes acceptable to the modern palate.

You can read it yourself one photographed manuscript page at a time here. The illustration on this page is for "Conynges (conies=rabbits) in clere broth." You can see the title clearly.

On September 23, 1387, Richard held a feast, the details of which are given. The pomp and ceremony started at 10:30, followed by:

• Venison with furmenty (a sauce of boiled wheat)
• A potage called Viaundbruse (a broth with choice meats)
• Heads of Boars
• Great haunches of roasted meat
• Roasted swans
• Roasted pigs
• Custard with dried fruit, parsley and bone marrow in a crust
• A subtlety (a decorative piece of food)

...and that was the first course. Eleven more dishes followed—mostly meats—and then a subtlety. Then a third course of ten more dishes, and a subtlety. When this was all done, the sun was beginning to fade. Wafers and spiced wine were served, and spiced confections placed on the tables.

That was a feast!


*The EETS was founded in 1864 by F.J.Furnivall with the stated goal of putting into print all historical manuscripts available in English. It is through the EETS that many manuscripts from the Cotton Library became available to scholars and the public.

More than a Musician

We so often study famous people in isolation, forgetting that their lives and successes probably overlapped other well-known people. Imagine the possibilities when people of vision and ingenuity met with and influence each other?

Philippe de Vitry (1291-1361) is not a well-known name today, but in his lifetime he was acknowledged as the greatest musician of the age, and his own works and his connections with others are worth knowing. In his lifetime, he was a diplomat, a soldier, a poet, a composer and music theorist. Like most university-educated men of the Middle Ages, de Vitry was in Holy Orders and held several clerical positions, finally being appointed Bishop of Meaux by Pope Clement VI.

Some of the motets he composed have survived. His chief contribution to music, however, was in the evolving system of notation. In Ars nova notandi (Art of the new notation), de Vitry improved on Franconian musical notation that had been set out in Franco of Cologne's Ars Cantus Mensurabilis (The Art of Measurement of Songs); de Vitry recognized the existence and importance of duple and triple meter. For connoisseurs of music:

In the treatise Vitry recognizes the existence of five note values (duplex longa, longa, brevis, semibrevis, and minima), codifies a system of binary as well as ternary mensuration at four levels (maximodus, modus, tempus, prolatio), and introduces four time signatures. He also discusses the use of red notes to signal both changes of mensural meaning and deviations from an original cantus firmus. (source)

And of course he knew other accomplished figures of his age, such as Petrarch, Nicholas Oresme, and Gersonides. In fact, de Vitry's musical approach to mathematics (the two subjects were closely linked in medieval education) prompted him to request of Gersonides a work to prove a theory. This 1342 work, De harmonicis numeris (On the harmony of numbers), maintained that, "except for the pairs 1-2, 2-3, 3-4, and 8-9, it is impossible for two numbers that follow each other to be composed of the factors 2 and 3." (source) The result is known today as the Theorem of Gersonides.

How far are the stars?

Rabbi Levi ben Gerson, also known as Gersonides, lived from 1288-c.1344. He was from a family of scholars: his father, Gerson ben Solomon of Arles, was the author of the Sha'ar ha-Shamayim, an encyclopedia of natural science, astronomy, and metaphysics.* Levi is credited with first mentioning, and possibility inventing, Jacob's Staff. (He references Genesis 32:10 when he describes the device; this is likely the origin of the name.)

At a time when religion, philosophy, astronomy, astrology and science were overlapping (and in some cases, interchangeable), Gersonides' greatest work, which was philosophical, contained his greatest contribution to astronomy. He put twelve years (1317-28) of effort into the Milhamot Adonai ("Wars of the Lord"), whose six books dealt with 1) the soul, 2) prophecy, 3) & 4) god's knowledge of facts and providence, 5) astronomy/astrology, and 6) creation and miracles. Gersonides firmly accepted astrology and the celestial hierarchy of powers inherited from neo-Platonists and pseudo-Dionysius (far too complex to go into here), but he also brought mathematics and observation to his work with extraordinary results for the time.

Postage stamp honoring Gersonides.

Gersonides rejected the Ptolemaic system of epicycles to explain the erratic motion of planets affixed to their crystal spheres surrounding the Earth. According to Ptolemy, epicycles explained the changing size of planets; he said, however, that Mars varies by a factor of six; Gersonides' observations told him that Mars's apparent size varies only two-fold. Gersonides used the Jacob Staff and a camera obscura (pinhole camera) to make careful observations over several years. For Gersonides, 48 crystalline spheres were needed to explain the apparent motion of various heavenly bodies. This expansion of the "physics" of the Ptolemaic model was nothing, however, compared to the actual physical expansion he proposed.

Careful observation with the Jacob Staff, the camera obscura, and math made Gersonides declare heavenly objects to be much farther away than previously calculated. Ptolemy claimed the distance to Venus was 1079 Earth radii; Gersonides estimated it to be 8,971,112 Earth radii away. Ptolemy said the fixed stars were 20,000 Earth radii away; Gersonides estimated them to be at a distance 10 billion times greater.

Pope Clement VI had the "Wars of the Lord" translated into Latin in 1344, making it available to the west. Its impact was minimal, however; we know of a few scholars who were influenced by it, and Kepler asked a friend to send him a copy in the 17th century. But it took Copernicus two centuries later to "confirm" to Western civilization's satisfaction that Gersonides was on the right track.

*As I have mentioned about medieval encyclopediæ before, they were often compilations of previous works; this one drew from Claudius Ptolemy's Almagest and the Morah Nebukim, or "Guide for the Perplexed" of Maimonides. A 1547 edition of ben Solomon's work can be had from Kestenbaum & Company.

Muslim-Christian Relations, Part 2 (of 2)

[Part 1 is here.]

Saladin

After Richard and Saladin each slaughtered their prisoners, Richard marched to Jaffa, which he hoped to make a base from which he could take Jerusalem. Saladin attacked, but Richard prevailed with his main troops in the front and the Knights Templar forces on the left and the Knights Hospitaller on the right. Saladin was surrounded on three sides. Richard took Jaffa in September 1191, and Saladin was willing to talk truce.

Richard and Saladin showed great mutual respect for each other's military prowess. A temporary halt to hostilities was declared so they could come to terms.  At one point, when Richard became ill, Saladin sent him fruit that was chilled with snow brought from the mountains, and offered his personal physician. Also, Saladin sent two horses as replacements for Richard's.

An attempt was made to join East and West by the marriage of Richard's sister, Joan (1165-1199), to Saladin's brother, Al-Adil (1145-1218), who was currently administrator of Egypt. Joan had been married to King William II of Sicily, but he had died in 1189; later she would become Countess of Toulouse by her marriage to Raymond VI. The plan was for Jerusalem to be their wedding gift, and would therefore pass into the hands of a dynasty that joined Western Europe (or, at least, England!) to the Muslim world. Negotiations fell through, however.

The two commanders did agree on a three-year truce. In summer 1192, the Treaty of Ramla determined that Jerusalem would remain under Muslim control, but Christians would be allowed safe passage. Also, the Crusaders would give up lands they had invaded except for a narrow coastal strip that extended from Tyre to Jaffa. Neither leader was wholly pleased, but each had reason to wish a swift end to the conflict. Richard had troubles at home due to his brother John. Saladin was losing control of his army because of his failure to re-take Acre or to route Richard's forces in their many engagements.

Saladin died of yellow fever in 1193. While his heirs fought over the succession, Western Europe was told tales of Saladin's military prowess and chivalrous actions toward the invaders. There is an anecdote that, in April 1191, a Frankish woman on pilgrimage had her baby stolen and sold into slavery. According to Saladin's biographer, Saladin bought the baby back with his own money and returned it to the mother, then ordered a horse to take her back to her camp. Poems were written in praise of him. Richard declared him the greatest leader in the Islamic world.

And the punchline? All the negotiations and gifts between Richard and Saladin were made by proxies. The two men who so praised and respected each other never met face-to-face.

Muslim-Christian Relations, Part 1 (of 2)

The Second Crusade (1145-49) had put a great deal of the Holy Land under European rule, but Saladin (Salah ad-Din Yusuf ibn Ayyub, 1138-1193) had re-conquered much of that territory, prompting several kings of Europe to agree to another crusade. The Third Crusade (1189-92) was unsuccessful in putting the Holy Land under Western European control. It did, however, open up a dialogue between the east and west in unforeseen ways.

The death of Henry II put the English troops under the command of Richard the Lionhearted. Richard loved military campaigns. His first stop was at Cyprus to conquer that island, after which he joined King Philip of France and Leopold V of Austria, who were embroiled in the two-year-long Siege of Acre. Richard's siege machines started destroying the walls. The residents of Acre sent appeals to Saladin to help them, but he could not defeat the Europeans. Acre had no choice but to surrender. Five weeks after Richard's arrival, the Europeans took the city, and banners were raised over the city representing the Kingdoms of Jerusalem, France, England, and the Duchy of Austria.

Richard may have been a great commander, but he was a terrible co-commander. The three lords fought over the disbursement of the spoils of war. Richard argued against the other two over whom should be left as King of Jerusalem; Richard prevailed. Richard also refused to accord Leopold the same respect as a king, and took down Austria's banner. In August, Philip and Leopold had had enough: they went back home, leaving 10,000 French troops with Richard's army.

Richard alone was left to deal with Saladin and establish a treaty after Acre. Payments of money and the transfer of Muslim and Christian prisoners were arranged. Richard did not like the slowness of the payments, and the fact that he wanted more Christians handed over faster. He had 2700 Muslim men, women and children of Acre killed outside the walls. Saladin, not to be outdone, killed all the Christians in his possession.

But the relationship between these two commanders was going to take an odd turn.

[to be continued]