Saturday 19 January 2013

Medieval Glasses and Viking Reading Crystals

As a leatherworker, I get extremely interested when I hear the phase "leather framed glasses".  I never knew such a thing existed until a few days ago, when I saw a link to an article discussing a rare book containing an even rarer imprint of glasses.  Yes, someone, several hundred years ago, shut their glasses in the back of a book they'd been reading:

 Impression of glasses left in the endpapers of a copy of the Opera of Fr. Luigi di Granata (1568-69).  This copy uses a page from an older manuscript.  It was pretty common for printed books of this time period to reuse old manuscripts for endpapers or as spine liners.  Photo by Pete Smith.  Original article:  http://www.utexas.edu/opa/blogs/culturalcompass/2012/04/17/medieval-spectacles/

The speculation is that these were leather framed glasses, an invention that was certainly in use in the 15th and 16th centuries.  It certainly makes you wonder how long those glasses remained in there before someone removed them though.  I also wonder how unobservant someone would have to be to lose their glasses in such a way...

Still, glasses are definitely up there in the most important inventions of the last 2000 years.  They were likely invented in Italy between 1268-1289, based on contemporary sources such as paintings and even sermons.  Although none of these early spectacles have survived (the earliest pair we have being from around 1400), we know that The Guild of Crystal Workers in Venice adopted the term "roida da ogli" in 1300 to refer specifically to lenses for glasses.

Before glasses were developed, however, monks had been using reading stones.  These were basically medieval magnifying glasses:

Between 1000 and 1250, presbyopic monks used reading stones, often made of beryllium or quartz, to read and work on manuscripts.  It would take another two centuries before someone thought to stick smaller versions of them into frames that sat in front of the eyes.

It was thought that these reading stones were mostly the property of monks, however, a set of crystal lenses made from quartz showed up in Viking graves in Visby, Gotland (Sweden).  Now, in fairness, Vikings were known for their love of pillaging monasteries.  They also had trade links though, which we often forget about.  Archaeologists believe that the lenses came from Byzantium or the Middle East, although unfinished lenses and rock crystal beads were found in 1999 in Frojel, meaning that someone could have been making them on Gotland.  The nifty thing about these lenses is that these people didn't have the mathematical knowledge to create them, still believing that light emanated from the eyes, rather than entering them.  They must have created these things through trial and error alone -- and it's believed that the know-how to do so was restricted to only a handful of craftsmen, if not only one at this time.

A range of the lenses found at Visby, although sadly, the largest and most impressive one has been lost since the 1950s.  Some of these were mounted and hung from pendants.  The others may have been waiting for mounting or were left deliberately unmounted.  Likely used for magnification, however, they could also have been used for starting fires or just as decoration.

Work undertaken at Aalen University of Applied Sciences concluded that although the mounted lenses were most likely used only as jewelry, the larger, unmounted lenses are shaped just like a modern projector lens.  The shaping was also deliberate, not accidental, so it's very difficult for the scholars to believe that these items weren't intended  to work as visual aids.  Certainly not during a time when such items did not commonly exist.

Refractive bling:  An aspheric lens mounted in silver, found in the graves in Visby, Gotland.  The lenses are suspected to be older than their mountings.  On the decorative pendants, like this one, the back of the mount is not open, but polished silver.  This smaller lens is purely decorative.

Either way, there's no disputing that if I were a Viking with a sight problem living on Gotland, I'd want one of these bad boys to help me see to do my crafts.  Also, it must be said that the smaller mounted lenses are really very pretty.  I'm a sucker for Viking bling, what can I say?




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5 comments:

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