Through the lens of history

Accounting for progress in Renaissance culture

By Hope Green

Thanks to such cultural luminaries as Michelangelo and Leonardo da Vinci, Renaissance Italy gave rise to whole new ways of looking at the world.

And when some clever soul in 15th-century Florence ground the first concave lens to correct nearsightedness, seeing that world became a whole lot easier.

The invention of spectacles was among several important, if less widely celebrated, gifts to Western civilization discussed at an April 26 Boston University symposium, which had as its theme Literacy and Numeracy in Late Medieval Italy.

"Eyeglasses had a number of interesting interactions with literacy," notes Thomas Glick, CAS professor of history. "For one thing, they extended the productive careers of scholars by decades. They also had implications for literacy and scholarship that affected the entire reading public."

Glick is director of the Institute for Medieval History, which cosponsored the symposium with the BU Interdisciplinary Italian Studies Program and the Pirandello Lyceum of Massachusetts. All of the presenters gathered to address what Glick calls a "huge cognitive shift" that accompanied the growth of Mediterranean trade during the Renaissance.

Large-scale commerce in Florence, Genoa, and Venice encouraged a focus on measurement and a theory of value, he explains. This was the era when systems were devised to lend and insure money, and a standard unit of currency was developed so that merchants could price disparate items, such as an apple or a piece of furniture, using an agreed-upon scale of worth.

As early as the 14th century, mechanical clocks installed in public places encouraged a more uniform measurement of time, Glick adds. Employers could then pay their laborers by the hour instead of by the piece.

Underlying these innovations was the introduction of our present numbering system. "The cognitive world was being shaped by Indian [also called Arabic] numerals and everything that went with them," Glick says.

Medieval merchants were chiefly responsible for transmitting Indian numeracy to the rest of the population, he explains, and the concept of zero and other aspects of the novel arithmetic "gave merchants the math techniques they needed to make increasingly complex calculations when doing overseas commerce, such as letters of credit, insurance, and currency exchange rates."

Counting dough

The advent of this commercial arithmetic was the topic of two symposium presentations, one by Lenore Feigenbaum, a Tufts University mathematics professor, and the other by Maristella Botticini, CAS assistant professor of economics.

Maristella Botticini Photo by Kalman Zabarsky

"I think we can really learn a great deal from studying the Renaissance economy," Botticini says, "because it was an important time for the development of banking and commerce."

In her presentation, Botticini explained how the advent of double-entry bookkeeping changed the way Europe did business.

"It was a revolutionary technique," she says. "In the past, merchants had had no way of calculating their profits and losses. It's amazing, because we are still using that same method today."

New vision

The Institute for Medieval History, says Glick, has an ongoing interest in what he calls "metatechnologies," or the basic skills that were the foundation for all science and technology in the Middle Ages. But this does not rule out a study of the technology itself. Thus, capping off the symposium, Vincent Ilardi, professor emeritus of history at UMass-Amherst and an adjunct professor at Yale, was scheduled to speak on Renaissance Vision With Florentine Eyeglasses: Spectacles and Literacy in the 15th Century.

Ilardi's main area of research is the history of diplomacy. But in 1976 he took on a subspecialty of sorts when he stumbled across a dispatch from a 15th-century duke of Milan to his ambassador in Florence. The nobleman requested three dozen pairs of eyeglasses to give out as gifts; his son ordered another 200 pairs.

With additional archival documents he collected from around the world, Ilardi helped to prove that concave lenses for nearsightedness were in use much earlier than previously believed, and that Florence, rather than Venice, was the leading manufacturer of spectacles in the Middle Ages.

"Historians of science are interested in the diffusion of ideas -- when did one invention lead to another -- and every year they keep sending me more documents to look at," he says. "They call me the eyeglass man."

Ilardi has used the information to trace the history of the telescope, which requires a combination of convex and concave lenses. Arcane as the topic may seem, Ilardi is distilling his 24 years of research on optical instruments into a book.

The Pirandello Lyceum has funded scholarly research at BU in the past, but this was the first time it cosponsored a symposium at the University. Glick said the event was intended to attract a large contingent from Boston's Italian-American community as well as a scholarly audience.