The Theory of Impetus

1582 woodcut demonstrating
impetus with artillery

Impetus is the force or energy with which a body started to move. The term itself entered the English language in the 17th century, but the concept was studied long before that.

Aristotle thought that, for an object in motion to continue to move, it must have a continuous force behind it. John Philoponus in the 6th century thought rather that the initial force was necessary and did not need anything else, but that the initial force would therefore be only temporary; hence an object in motion's observed tendency to slow and stop. Avicenna in the 11th century agreed with him, calling the phenomenon "projectile motion."

In the 12th century, an Islamic philosopher, Hibat Allah Abu'l-Barakat al-Baghdaadi, recognized (finally!) that the motive force diminishes with distance from the mover.

Jean Buridan, writing in French in the 14th century, called this force "impetus" (from Latin impetere, "to assail"), and even expressed it mathematically: impetus = weight x velocity. Even he, however, treated impetus as if it were momentum. Modern physics distinguishes the two thusly: impetus is the initial force behind a moving object, momentum is "the quantity of motion of a moving body." It seems universally understood by anyone who has ever thrown a ball that Aristotle's option of a continuous motivating force is simply quaint.

Buridan understood that there was resistance (such as the air) that caused the impetus to fade. There was a case, however, in which impetus did not have resistance. God, when putting the celestial spheres in motion, did so in a way that created infinite impetus so that they would (obviously!) never stop moving.

To which the medieval world replied: Thank Heavens.

Birth of a Medievalist

This is a slightly different tack for DailyMedieval, but many fans of his fiction are unaware of his career as a medievalist.

John Ronald Reuel Tolkien (3 January 1892 - 2 September 1973) graduated college with a specialty in Old Norse before he went not fight in World War I. After the war, his first job was working for the Oxford English Dictionary, reviewing the history and etymology of Germanic words. He became an expert in Old Norse, Old English, Middle English, Old Icelandic, Gothic, and Medieval Welsh. He also taught himself some Finnish.

Later, at the University of Leeds, he produced A Middle English Vocabulary and a translation of the poem Sir Gawain and the Green Knight that is still in print.

One of his most significant additions to medieval studies was his long essay "Beowulf: The Monsters and the Critics." Delivered as a lecture in 1936, it argued for the beauty of the poem as Early English literature. Up to this point, Beowulf had been used largely as a primer on the language of Old English/Anglo-Saxon, and picked apart for its references to places and names that could be matched to historical facts.

He describes the attitude toward the poem with a parable:

A man inherited a field in which was an accumulation of old stone, part of an older hall. Of the old stone some had already been used in building the house in which he actually lived, not far from the old house of his fathers. Of the rest he took some and built a tower. But his friends coming perceived at once (without troubling to climb the steps) that these stones had formerly belonged to a more ancient building. So they pushed the tower over, with no little labour, in order to look for hidden carvings and inscriptions, or to discover whence the man's distant forefathers had obtained their building material.

His essay created an atmosphere in which Beowulf could be seen as a poem worthy of being treated as a poem, not as an old document to be studied simply for clues to language and criticized as a dish-mosh of paganism and Christianity, mingled stories of heroism and monsters, history and myth.

Ultima Thule

A 1537 rendition of Thule

On New Year's Eve 2018, a NASA probe transmitted pictures of Ultima Thule, an object 4 billion miles from Earth. "Ultima Thule" is not your typical astronomical naming convention.

Ultima Thule, or the "ultimate Thule," was first described about 300BCE by a Greek explorer named Pytheas. It was supposedly about six days north of Britain, a place so far from the natural world that land and sea and air were no longer separate substances, but instead formed a strange mixture in which one could not survive.

A thousand years after Pytheas, Isidore of Seville (mentioned here, also involving astronomy) explained Ultima Thule as being so far north that there was no daylight beyond it, making the sea cold and sluggish.

As stories of explorers (verified or not) appeared, Thule was identified and re-identified with lands farther and farther from mainland Europe. St. Brendan's voyages suggested new lands that historians thought might refer to Thule. The later Middle Ages decided it must refer to Iceland or Greenland. In early modern times, Norway became the candidate to explain early stories of a land that far north.

In the 20th century, the idea of Thule was co-opted by certain German writers and politicians as the legendary origin of the Aryan race. Fortunately, the 21st century has given it a new connotation.

Why a Boar's Head?

From a feast at the University of Rochester

Most readers of this blog will be familiar with the Boar's Head Carol.

The version we use most often today (there are slight variations, including a version for serving poultry) was recorded in a book of Christmas carols printed in 1521. It has been a popular carol—and a Yuletide event—ever since.

At least one scholar links it to a Norse tradition brought to England with the Anglo-Saxons. Sacrificing a boar to Freyr, a Norse god amenable to mortals, was supposed to bring peace and prosperity in the new year.

There's another origin for the choice of a boar, which has a slight hint in a line in the carol itself. In a book about Christmas carols printed in 1868, we can read the following:

Where an amusing tradition formerly current in Oxford concerning the boar's head custom, which represented that usage as a commemoration of an act of valour performed by a student of the college, who, while walking in the neighbouring forest of Shotover and reading Aristotle, was suddenly attacked by a wild boar. The furious beast came open-mouthed upon the youth, who, however, very courageously, and with a happy presence of mind, thrust the volume he was reading down the boar's throat, crying, "Græcum est," [Latin: "compliments of the Greeks"] and fairly choked the savage with the sage.  [Husk, William Henry. Songs of the Nativity Being Christmas Carols, Ancient and Modern]

I have included translations of the Latin lines below. The final one refers to Queen's College in Oxford. Husk was the librarian at Queen's College.

The boar's head in hand bear I,
Bedeck'd with bays and rosemary.
And I pray you, my masters, be merry
Quot estis in convivio [You who all feast in harmony]

CHORUS
Caput apri defero [The boar's head bear I]
Reddens laudes Domino [Singing praise to God]

The boar's head, as I understand,
Is the rarest dish in all this land,
Which thus bedeck'd with a gay garland
Let us servire cantico. [serve with a song]

CHORUS

Our steward hath provided this
In honour of the King of Bliss;
Which on this day to be servèd is
In Reginensi atrio. [in the Queen's hall]

Was THIS Robin Hood?

Statue in Nottingham

We have established that the first mention of Robin Hood is in the 1370s. And in the mid 1400s, someone places him in 1283 living in "English Woods." In the legends as they developed later, Robin (along with a band of men) lives in Sherwood Forest, is opposed to an authoritarian king, and is opposed by the Sheriff of Nottingham. Supposedly, he is living in the time of Bad King John, and is saved from prison when Richard Lionheart returns from Crusade.

Was there anyone who acted in the manner we ascribe to the legendary Robin Hood, who lived about that time? Let me tell you about Roger Godberd. What we know about him starts with the Second Barons War.

The Second Barons war (1264-67) was all about curtailing Henry III's grasp as he requested more and more financing from his vassals. One of the chief battles was the Battle of Evesham in 1265, led by Henry's son, the future King Edward I. In it, one of the leaders of the barons, Simon de Montfort, was killed in that battle.

Roger Godberd was in the forces of de Montfort, and was declared by the Crown to be an outlaw after Evesham. He went on the run, settling in 1265 in Sherwood Forest in Nottinghamshire. It was said that he was able to call on a hundred men to support him. He managed to elude the king's forces for four years.

A common Robin Hood story is of his capture at an abbey, and subsequent escape with the help of his men. Godberd was captured at Rufford Abbey by Reginald de Grey, the Sheriff of Nottingham. He escaped when a local knight named Richard Foliot came to his aid.

Godberd was eventually imprisoned and tried at the Tower of London. He was pardoned by none other than the man who led the forces at the Battle of Evesham. Now King Edward I, he pardoned Roger upon Edward's return from the 8th Crusade.

Robin Hood and the Monk

Although most depictions of Robin Hood place him in England when Richard Lionheart was away on Crusade and King John was messing up the country (the 1190s), there are no mentions of him in any literature until significantly later. The earliest is in Piers Plowman in the 1370s, and then only with a reference to the "rhymes of Robin Hood."

About 1420, Andrew Wyntoun's Orygynale Cronykil of Scotland mentions "Lytil John and Robyne Hude" living in the "Yngol Wood" (English woods) in his entry for the year 1283.

What these rhymes/stories were at the time we can only guess. The oldest tale we have, "Robin Hood and the Monk," is from about 1450. In it, a devout Robin wants to go to Mass in Nottingham, and is warned by Much the Miller's son that he should take 12 men with him for safety. He only takes Little John. Along the way they make a wager. Robin loses, refuses to honor the wager, and Little join leaves him alone. While praying at St. Mary's in Nottingham, the sheriff is called on him by a monk that Robin robbed on some earlier date.

Once Robin's men find out, they decide to rescue him. They find the monk, riding with a page. Little John kills the Monk and Much kills the page. The monk had letters for the king, which Little John and Much deliver, explaining that the monk died along the way. The king tells them to bring Robin to him.

Little John and Much deliver this message to the sheriff, explaining the monk's absence by saying the king made him an abbot. They enter the prison, kill the jailer, and free Robin, who pledges loyalty to Little John for being so good after Robin was so dishonest to him. Little John agrees to keep the previous arrangement of leadership. The king, learning of all this, is upset that he was hoodwinked, but decides to drop it.

We do not see any signs here of Robin being particularly good. But the story had adventure and plot turns, so it was fun to tell. It's a long time later when characters like Maid Marian and Friar Tuck get added, as well as the idea that he stole from the rich to give to the poor.

Andrew Wyntoun, Scot

When Robert Burns published his Poems, Chiefly in the Scottish Dialect (1786), no one knew that it would become such a success that the reading public would be eager to lap up anything old and Scottish. But 1790 saw the publication of the Orygynale Cronykil of Scotland, by Andrew Wyntoun.

Wyntoun (c.1350-c.1425) was an Augustinian canon of St. Sers Inch, a religious house  of Loch Leven, as well as a poet. The Chronicle is very pro-Scotland, especially regarding Edward I and his treatment of William Wallace and Scotland.

The Chronicle starts in the distant past (Alexander the Great, ancient Britons) and ends in 1420. It contains a number of "firsts": it is the earliest extant document in the Scottish dialect; it has the first use of the word "Catholic"; also, it contains the first mention in print of Robin Hood that ties him to a particular time (1283) and an area just south of the Scottish border in Carlisle. Tales of an outlaw who hides out in the woods and harasses the English king were of interest to the Scots, especially after William Wallace et alia did the same after Dunbar and Falkirk. It also includes the earliest version of MacBeth and the three witches.

Rabies

Rabies, from the Latin rabies which means "madness," has been noticed for a long time. The Codex of Eshnunna (c.1930BCE), found on two cuneiform tablets and pre-dating the Code of Hammurabi, declares the owner of a dog who shows signs of rabies is to be fined if the dog bites someone. Aristotle in 300 BCE described rabies as a disease that can be transmitted from a dog to the dog's victim. Excess salivation was a sign that a dog owner should take care to prevent the dog from biting someone. Rabies was known to Avicenna, who explained its symptoms, method of transmission, and treatment.

Treatment almost always failed until the modern era. There were reported cases of people surviving before modern methods of treatment, but not until Louis Pasteur and Émile Roux developed their vaccine in 1885 was there an effective way to prevent the spread.

But the Middle Ages had a solution: St. Hubert's Key.

St. Hubert, or Hubertus, was the patron saint of hunters and hunting, and therefore of hunting dogs, and therefore of rabid dogs. St. Hubert's Key was an example of a sacramental, which is the church's word for an amulet or talisman. Whereas an amulet or talisman were supposed to have magical properties, a sacramental's effectiveness depended on the faith of the user.

St. Hubert's Key was a piece of iron: either a nail or a cross or cone. They were given out by the monks of the Benedictine abbey where Hubert's remains were, as tokens to go to folk who could not make the pilgrimage to the abbey. These items were hung on the wall of your house for protection against disease.

How did this cure rabies? The piece of iron would be heated and placed on the site of the bite by a priest. The practice is recorded in the 1870s in the Ardennes region (where Hubert was active while alive) of branding a dog with St. Hubert’s Key to guard him from rabies.

Patron Saint of Hunting

...and of mathematicians, and opticians, and metalworkers, and more.

Saint Hubertus' conversion from materialism to piety was first discussed here. After he died, on 30 May 727, his bones moved around a bit. He was buried in the church of St. Peter in Liège, but his bones were exhumed so they could be interred in a Benedictine abbey (now named St. Hubert's Abbey) in the Ardennes region. The Ardennes was important to him—his nickname was the Apostle of the Ardennes—because he originally loved to hunt game there. After his conversion he "hunted" folk in the region to be convert them to Christianity. He would not destroy their "idolatrous" sites, but give the converted the opportunity to destroy the sites themselves as proof of their new love for Christianity.

His coffin became a focal point for pilgrimages, until it disappeared during the Reformation. Just as his physical remains were disappearing from view, however, his spiritual reputation was building. Because he was of royal birth, he was considered one of the Four Holy Marshals in the Rhineland. (That's for another day.) Several military orders were founded in his name. In the Church of England, at least two churches were dedicated to him. There is a St. Hubertus brand of alcohol, and the image of the stag with the cross between his antlers is their logo.

Although he is most commonly referred to as the patron saint of hunters, he is also given patronage for an amazing and varied number of other areas. Here is the full list:

against dog bite	furriers	opticians
against hydrophobia	hunters, huntsmen, & hunting	precision instrument makers
against mad dogs	forest workers	metal workers, smelters
against rabies	trappers	Liege, Belgium
archers	machinists	Saint-Hubert, Belgium
dogs	mathematicians

I cannot find an explanation for the link to optics, but I can tell you a story about him that involves metal and connects to some of his prominent patronage areas. I'll get to that next.

Saint Hubertus

Saint Hubertus (c.656 - 30 May 727), also called the Apostle of the Ardennes, was said to be the eldest son of Duke Bertrand of Aquitaine. He was a well-liked young man who found fame and position wherever he went, ultimately being named "grand-master of the household" at the court of Austrasia at Metz, marrying the daughter of a count. His wife, Floribanne, died in childbirth, causing Hubertus to withdraw from public life out of grief. He went to the forests of Ardennes and lived by hunting.

Then, on the morning of a Good Friday, when the faithful were thinking of spiritual matters, Hubertus went out to hunt. Spotting a magnificent stag, he started pursuit, but the animal turned to face him. Hubertus beheld a cross suspended between its antlers. A voice spoke: "Hubert, unless thou turnest to the Lord, and leadest an holy life, thou shalt quickly go down into hell!"

This anecdote was linked to Hubertus in the 15th century. It is connected at a much earlier time to the legend of St. Eustace from the 2nd century. (The historicity of Eustace was eventually challenged, but there was no sense letting a good conversion anecdote go, so it got attached to the life of a known hunter.)

Later reports embellished the story, especially in Germany, where it is said that the deer lectured Hubertus on responsible hunting, with rules still taught in Germany today:

Only shoot when you can be sure of a quick and painless death
Choose older stags, past their prime
Never kill a doe with fawns

Hubertus found Bishop Lambert in Maastricht, who became his spiritual mentor. This is when Hubertus left the position of Duke of Aquitaine to his younger brother, Odo, as well as the guardianship of his son. Hubert later replaced Lambert as Bishop of Maastricht. He became famous for his preaching and piety.

As is often the case, however, men become even more prominent long after their death, which was the case with Hubertus. I'll discuss that next, and maybe discuss his odd connection to the Supreme Court of the United States.

Odo the Great

The Umayyad Caliphate at the time of Odo

This blog has mentioned several men named Odo in the past, but never "the Great." He was born in southwest Gaul and became the Duke of Aquitaine as early as 679, or maybe 688, or even 692, but for certain by 700.

Gaul was a land mass, not a country: in that space were numerous areas ruled by different men. Odo was at odds with the political entity we normally think of as ruling Gaul at this time: the forces under Charles "the Hammer" Martel, who was the powerful "Mayor of the Palace" of the Merovingians and whose grandson would be known as Charlemagne and unite much of Gaul under his rule.

Martel's claim to fame (or one of them) was preventing the Muslim invasion of Europe, especially at the battle of Tours in 733. But Odo had already made some progress in that area. Odo's territory was just north of what is now Spain, bordering the Caliphate of the Umayyads. On 9 June 721, Odo defeated a Muslim army under Al-Samh ibn Malik al-Khawlani at the Battle of Toulouse. He then married his daughter to a Muslim lord, Uthman ibn Naissa, making an alliance with the area that would become Catalonia. This seemed like a smart move.

Charles Martel didn't really hold with the idea of making friends with Muslims, however. Moreover, his goal was to possess more territory. He invaded Aquitaine in 731, and while Odo was being defeated by Charles, on his other border Odo's ally Uthman ibn Naissa was being attacked by Abdul Rahman Al Ghafiqi, who defeated Uthman and sent Odo's daughter to a harem in Damascus. As Abdul Rahman advanced, Odo engaged him and was defeated. He had no choice but to turn to Charles Martel for assistance, which was offered on the condition that Aquitaine swear fealty to Charles. So Charles wins at the Battle of Tours, and Odo fell into historical obscurity. In 735 or so he abdicated as Duke of Aquitane; we think he went to a monastery.

Odo was not the eldest son of the Duke of Aquitaine, and got the position when his older brother abandoned his rights to it. That brother was named Hubertus; I'll tell you about him next.

Medieval Advertising

These days, we are assailed by advertising, and we possess technology that allows us to find what we need merely by asking the right question into a hand-held device. (I wonder that anyone in their teen years knows what it's like to use the yellow pages, or if they are even aware of what the phrase "yellow pages" means to the older generation.)

Centuries ago, signs or symbols indicated certain places of business. When most of your population cannot read, you needed to find the right image to represent your profession, such as the mortar and pestle for an apothecary, a boot for a cobbler, scissors for a tailor, etc.

It might not be a painted sign. Roman custom was to hang vine leaves to indicate a tavern where wine was served. This custom was brought to Britain, but in the absence of grapevines they used holly. A bush of holly was a common indication that wine was served within. If you made and sold beer, you would hang a long pole outside, indicating what you stirred ale with. Leaves on a pole let the traveler know that both beer and wine were available.

Of course, where there is food and drink, there should be quality control.

In 1389, King Richard II of England, decreed that landlords must put signs outside their inns, so that inspectors could identify and visit them; there is a record from 1393 of a publican being prosecuted for not having a sign. [source]

Of course, not all advertising was static. A 13th century poet, Guillaume de la Villeneuve, wrote the poem "Les Crieries de Paris" [Street cries of Paris]. Here's a sample of how he felt about merchants advertising their wares or services:

Although they will not stop screaming
Through Paris until the night.
Do not think it tires them
For they will never stop.
Listen to what is being shouted at daybreak:
"Lords, go to the baths
And in the ovens without delay,
The baths are hot, I'm not lying!"
Then you will hear the sound [of]
Those who shout fresh herrings.
"At the tide, the others shout,
In sage and white herring, fresh salted,
I would like to sell my herrings."

The introduction of mass printing and cheap paper meant signs and flyers could circulate more easily, eliminating the need for criers.

Mincemeat

With the holiday season upon us, folk are preparing to consume mincemeat pies at the conclusion of their meal. Growing up, I was told it was a dessert made from ground up fruit and spices and not to think of it as meat, and I was never tempted by it. Imagine my surprise, years later, to discover:
1. "meat" wasn't a euphemism
2. it's not a dessert, but a main dish
3. I loved it

Numbers one and three might not be a surprise or noteworthy, but number two was worth looking into. King Henry V had a mincemeat pie as a main dish for his coronation feast, and Henry VIII apparently preferred it as his Christmas supper. Its creation goes back further, however.

You might say it originated by accident. Crusaders returning home in the 12th century brought with them spices not found in western Europe before. These were tested as preservatives for meat, or ways to add flavor to dried meat. (The notion that spices were used to cover up the small of rotten meat should be dispelled. No one would eat rotten meat, and we had learned ways to preserve the meat of slaughtered animals long before this, through smoking/drying or salting.)

Cinnamon, cloves, and nutmeg were the three chief spices used in the Yule dish, representing the gifts  brought by the Magi. These were added to minced (finely chopped) meat, often beef or beef tongue or lamb, as well as beef suet (the hard white fat from around the kidneys and loins). Early recipes add citrus peel and sugar, or dried and chopped apples.

Early pies were baked in an oblong shape, to represent the manger at the Nativity. Over time, the addition of sugar made them sweeter, and they began to migrate to the dessert course. At that point, they morphed into the traditional round pie shape, and then into tarts that could be easily picked up and eaten by hand.

Borromean Rings

You've seen them. Lots of times. Three circles interlinked. You find them in jewelry, and in the label of Ballantine beer. They may be used as a symbol of the Trinity, or the logo of the 25th International Congress of Mathematicians.

The name of the design comes from its use in the coat of arms of the Borromeo family. The family owns three islands in Lake Maggiore, and might have designed the rings to represent those. In any case, the design is used frequently in the Baroque palazzo and gardens built by Vitaliano Borromeo (1620-1690).

But the design goes back hundreds of years before Borromeo. We find its equivalent also in three triangles called "Odin's Triangle" or the valknut (Old Norse valr = "slain warriors" + knut = "knot"). The valknut was carved in stone pillars as far back as the 7th century.

One curious fact about the Rings is that, although we call them "interlinked" or "interwoven," they sort of aren't. In the above illustration, place your hand over the red as much as you can, and you'll see that the blue and green aren't linked. It's the same with any other two colors: no two are linked except by a third that runs through them. In this way, it is similar to a three-strand braid. Braid three ribbons together, and when you pull one out, the other two completely disengage.

And for a treat: how about some Borromean Onion Rings?

Eyeglasses

Back here we spoke about the manufacture of glass, but when and where did glass come to be used for enhancing and correcting vision?

Ptolemy (c.100-170CE) wrote in his Optics about glass shaped so that it enlarged an image. His ideas were expanded on by the "Father of Modern Optics," Hasan Ibn al-Haytham, whose Book of Optics (c.1021) spread through Europe at (coincidentally?) about the same time that we get records of "reading stones."

A reading stone is a glob of transparent substance, flattened on the bottom but with a curved top, making it in essence a convex lens. It was (still IS, actually) meant to be placed on and slid along a line of text, causing the letters below to expand and be more easily read. I call it a "substance" because it wasn't necessarily glass. Early ones were ground from quartz, and they can be had today in glass or plastic.

Several lens-shaped items of quartz have been found in Viking graves on Gotland in Sweden, some mounted in silver. They date to the 11th or 12th centuries. They might be reading stones, although several are not shaped to be good at focusing.

But when were lenses put into a frame for enhancing vision? In 1301, in Venice, there were guild regulations governing the sale of eyeglasses. The Dominican friar Giordano da Pisa delivered a sermon in February 1306 in which he said:

It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision... And it is so short a time that this new art, never before extant, was discovered. ... I saw the one who first discovered and practiced it, and I talked to him.

 So far as we can trace, then, eyeglasses were first made in Italy around 1290.