Purple Parchment and the Cave of Smoo

In the year 997, the excommunicated archbishop of Reims sent the Holy Roman Emperor a kingly gift: a copy of Boethius's On Arithmetic written in gold and silver inks on purple parchment. It had the desired effect. As I wrote in The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages, my biography of that archbishop, the 17-year-old emperor summoned Gerbert of Aurillac to court with the plea, "Pray explain to us the book on arithmetic." Archbishop Gerbert became the emperor's tutor, friend, counselor--and ultimately, through the emperor's influence, Pope Sylvester II, the pope of the Year 1000.

Earlier in this blog, I described how parchment and ink were made in the Middle Ages. (See "How to Make a Medieval Book, Part I" and "How to Make a Medieval Book, Part II.")

But purple parchment? How did they color the parchment purple? I hadn't given that much thought.

Then the other day, researching something quite unrelated--the Viking settlements in northern Scotland--I stumbled upon the answer.

In 1992, a team of archaeologists led by Tony Pollard excavated four neighboring caves in a narrow inlet in Sutherland, one being the famous Smoo Cave. (See the great website, from which these photos of the cave were taken, at www.smoocave.org) In 2005, Pollard posted their report online at www.sair.org.uk/sair18.

"Smoo" comes from the Old Norse word smuga, which Cleasby-Vigfusson, the classic Old Icelandic dictionary, defines as "a narrow cleft to creep through, a hole." The related verb is smjúga, "to creep through a hole" of which the past tense is smaug. Bells are now going off in the heads of all Tolkien readers--but I won't be following that digression any farther.

Back to Smoo Cave. Surprisingly, I had visited the cave in 1995. Two balding Scotsmen with rat tails and earrings took me on a river raft under a low stone arch, across a pool into which a sun-sparkled waterfall fell. In the dark cave, it was a real surprise. We disembarked in the dry inner reaches of the cave and had a geology lesson. The outer, larger cavern was made by the sea: the hole, wider at the bottom than the top, is a blowhole. The inner caverns were made by an underground river that feeds from a large lake. The waterfall only runs when there’s been rain—today’s fall is last night’s rain.

As Pollard points out, Smoo Cave has been a tourist attraction since at least the early 1700s. One practical-minded traveler described it as "stretching pretty far underground with a natural vault above." Inside, "there is room enough for 500 men to exercise their arms." (I'm imagining jumping jacks here--but maybe he means to practice their shooting?) There's "a harbor for big boats" at the cave's mouth, a pool full of trout, and "a spring of excellent water."

Earlier visitors also valued the cave for its usefulness--not its surprising bright waterfall. Pollard and his crew of archeologists found signs that Vikings had used Smoo Cave as a fishing camp, as well as a place to sit out a storm and repair a boat. They may have stopped here on their way from the Orkney Islands to Dublin. They butchered animals and cooked them. They ate dried fish they'd brought with them. They ground grain. They carved pins and knife handles and other useful objects out of antler and bone.

But the most interesting thing the Vikings did at Smoo and its neighboring caves was collect and crack open whelks. These were not just any whelks, but Nucella lapillus, also known as Purpura lapillus, the source since antiquity of a purple dye. These whelks are not edible, and they were not used as fish bait, Pollard says. "It is clear that purple dye was being extracted from the shells recovered from the cave."

The whelks, Pollard writes, "had been split from the second and third whorl and also split from the shoulder to the base.... This would have facilitated the removal of the animal from its shell to extract the ink."

In 1895, archaeologists found "Purpura-mounds" in Connemara, Ireland. The shells in the mounds had been broken exactly like those in Smoo Cave, though in Ireland there were many more of them. One heap measured 165 by 45 feet. In one square foot, the researchers counted two hundred whelks. Purpura-mounds have also been found in Cornwall, England, but Smoo Cave is the first record from Scotland, although the whelk is common there.

To learn how to make the dye known as Tyrean purple, Pollard refers the reader to the 1919 book, Shells as Evidence of the Migrations of Early Culture by J.W. Jackson. Like Pollard's own report, Jackson's book is available online. (Historical research is so easy these days!)

Jackson, in turn, cites the first-century Roman writer Pliny to explain that "the precious liquid was obtained from a transparent branching vessel behind the neck of the animal and that at first the material was of the colour and consistency of thick cream."

Several kinds of whelks produced purple dye. Small ones were smashed together in a mortar; if large, "the animal was taken out entire, usually by breaking a hole in the side of the shell, and the sac containing the colouring matter was taken out, either while the animal was still alive, or as soon as possible after death, as otherwise the quality of the dye was impaired." The sacs were salted, allowed to sit for three days, then boiled and frequently skimmed. Exposed to the sun, the fluid (smelling like garlic) slowly changed color, from creamy to yellow, green, blue, and finally a purplish red. After ten days, the dye was ready to use.

To dye wool, a clean fleece was dunked into the boiling dye pot and left to soak for five hours. It was taken out, cooled, and the wool plucked off and carded, only to be "thrown in again, until it had fully imbibed the colour" (still smelling like garlic--one reason the wearers of royal purple robes wore so much perfume, suggests Jackson). It took between one and two pounds of liquid dye to color a half-pound of yarn.

To turn parchment purple, Jackson says, the dye was used as a paint, applied with a brush. The "magnificent and expensive style of writing" on purple parchment with gold and silver inks was mostly confined to sacred texts. Jackson cites an English Bible and a Gospel book, another book of the Gospels commissioned by Louis the Pious, king of France from 814 to 840, and a Book of Prayers, "bound in ivory and studded with gems" owned by his son, King Charles the Bald.

It's significant that Gerbert of Aurillac, who would become "The Scientist Pope," owned a mathematical treatise made in this "magnificent" style. The book still exists in the Staatsbibliothek Bamberg in Germany, where it is catalogued as MS Bamberg Class. 5 (HJ.IV.12), but we don't know how it came into Gerbert's possession. Like the gem-studded prayer book, On Arithmetic was commissioned by King Charles the Bald in about 832. But the dedicatory verses apply equally to the young emperor Otto III as to King Charles, and scholars long thought Gerbert (known as a poet) had written them. Otto III may have thought so too, for he answered the gift with a verse.

Join me again next Wednesday at nancymariebrown.blogspot.com for another adventure in Iceland or the medieval world.

How to Make a Medieval Book, Part II

As I said last week, for me the hardest part of writing a book is deciding what to say. But in the Middle Ages, as I learned when researching the technology of book-making for The Abacus and the Cross, a lot more work was involved. Last week, we learned how to make the parchment for your book’s pages. Here’s how to make your ink and bind your book.

Ink

At the monastery of Saint Columban in Bobbio, Italy—which once held the greatest Christian library of the tenth century, with 690 books—Jessica Lavelli runs a project for schoolchildren called CoolTour. After they understand how to make parchment (see How to Make a Book: Part I), Lavelli’s pupils get to make their own manuscript. They copy a page from a tenth-century life of the founder of Bobbio, the Irish Saint Colomban. The page begins, Beatus ergo Columbanus, and the initial “B,” taking up a third of the page, is a maze of Celtic knotwork in red, blue, green, and black. For Beatus, the pupils substitute their own names; they fill out the rest of the line any way they like.

Lavelli does not supply authentic medieval inks. “The kids write their names using goose quills and common black ink. Then we give them paintbrushes, and vinegar and egg white to mix the colors, which we buy at an artists’ shop. The colors are not easy to find,” she added, “and it can get very expensive if you want to make your own.”

In the Middle Ages, black ink was made from oak galls—the black bubbles you find on an oak twig where the gall wasp has stung it to lay its eggs. The galls were ground, cooked in wine, and mixed with iron sulfate and gum arabic. Oak galls contain gallic acid, which causes collagen to contract; instead of sitting on the surface, the ink etches the words into the parchment. Crushed iron sulfate (often found together with pyrite) makes the ink black; gum arabic, the sap of the acacia tree, makes it thick. Another recipe called for vinegar and rind of pomegranate. Egg white (preserved by a sprig of cloves) and fish glue were used, in addition to gum arabic, to thicken colors; other common ingredients were ear wax, pine rosin, lye, stale urine, and horse dung.

To make the red ink commonly used for titles, you have to grind and cook “flake-white,” a white crust that forms on lead sheets hung above a pot of simmering wine. To make green, you need copper filings, ground egg yolks, quicklime, tartar sediment, common salt, strong vinegar, and boy’s urine. An expensive blue was made by grinding up lapis lazuli; a cheaper variety could be made from the woad plant, which contains the same chemical as indigo. Yellows were made from the plants weld or saffron, or from unripe buckthorn berries. Purple came from the herb turnsole, brick red from madder root, and pink from brazilwood, while earth colors came from filtered and roasted dirt.

The parchment made, the ink mixed, an expert scribe could write at the rate of forty strokes (five to six words) a minute, which over a six-hour day adds up to two hundred lines per day. Michael Gullick, in Making the Medieval Book, came up with these numbers by counting the lines in a manuscript that a scribe claimed to have written entirely by his own hand in a month. Doubting that anyone could maintain that speed, Gullick asked the calligrapher Donald Jackson for a second opinion. Jackson had worked with quill and parchment for thirty years. He copied lines from the manuscript, taking into account the height of the strokes, the line length, and “the finesse and skill of the scribe.” Jackson estimated the maximum possible speed at twenty-five lines an hour. If the scribe really finished the book in a month, he concluded, he had worked eight hours a day every single day.

And that was just for the text. Illustrations and the fancy initial capitals, like the B for Beatus, were usually done by a different monk, who specialized in drawing. A scholar who examined one luxurious book of psalms found it to be the work of three scribes, a rubricator (who did just the red titles), and nine artists.

Bookbinding

Finally the finished pages were sewn into quires (often gathered together with the text of several other books on the same or different topics) and bound between boards of oak or beech. The inside of each board was covered with a fly leaf or pastedown, a piece of fresh parchment or (more often) one recycled from an unwanted manuscript. Sometimes these old sheets were cleaned first, by soaking them in whey or orange juice and scraping off the inks and colors; fortunately, this was not always done—more than one precious leaf has been saved because it was recycled.

The outsides of the boards were covered in leather (alum-tawed pig’s leather was preferred, because it was white) and fitted with metal clasps to keep the book from popping open. Then it would be locked away in a wooden bookchest to protect it—not from thieves, who could open the chest with an axe, so much as from borrowers who might “forget” to return it. For a book was a very valuable thing. A historian who tried to calculate exactly how valuable, found a law book that was bought for eight denaris: the price of ninety-six two-pound loaves of bread.

The bread I buy from a local bakery is about $5.00 a loaf, making the cost of that law book today about $480. My book The Abacus and the Cross, on the other hand, costs $28—in hardback. The paperback, due out in October, will be only $17, just a little more than three loaves of bread.

If you visit Bobbio, check out CoolTour and say hello to Jessica for me:

http://www.cooltour.it/

For an overnight stay, I recommend the farm guesthouse San Martino. It is (of course!) a horse farm within walking distance of the town:

http://www.agriturismo-sanmartino.com/

Bobbio has also been recently identified as the town painted in the background of the Mona Lisa. As one newspaper said, “brace for tourists”!

http://www.newser.com/story/109501/art-historian-identifies-mona-lisas-home-town.html

Photos: Detail of a Bobbio manuscript and portrait of a scribe, both from the CoolTour Bobbio website.

Join me again next Wednesday for an excursion into the medieval world at nancymariebrown.blogspot.com