Rare eleventh-century astrolabe discovery reveals Islamic–Jewish scientific exchange

Dr. Federica Gigante, from Cambridge University's History Faculty, made the discoveries in a museum in Verona, Italy, and published them today in the journal Nuncius.

Dr. Gigante first came across a newly uploaded image of the astrolabe by chance on the website of the Fondazione Museo Miniscalchi-Erizzo. Intrigued, she asked them about it.

"The museum didn't know what it was and thought it might actually be fake," Dr. Gigante said. "It's now the single most important object in their collection."

"When I visited the museum and studied the astrolabe up close, I noticed that not only was it covered in beautifully engraved Arabic inscriptions but that I could see faint inscriptions in Hebrew. I could only make them out in the raking light entering from a window. I thought I might be dreaming, but I kept seeing more and more. It was very exciting."

"This isn't just an incredibly rare object. It's a powerful record of scientific exchange between Arabs, Jews, and Christians over hundreds of years," said Dr. Gigante.

"The Verona astrolabe underwent many modifications, additions, and adaptations as it changed hands. At least three separate users felt the need to add translations and corrections to this object, two using Hebrew and one using a Western language."

Astrolabes were the world's first smartphone, a portable computer that could be put to hundreds of uses. They provided a portable two-dimensional model of the universe fitting in their user's hand, enabling them to calculate time and distances, plot the position of the stars, and even forecast the future by casting a horoscope.

The Verona astrolabe. Credit: Federica Gigante

Close up of the Verona astrolabe showing inscribed Hebrew, Arabic and Western Numerals. Credit: Federica Gigante

Close up of the Verona astrolabe showing Hebrew inscribed (top left) above Arabic inscriptions. Credit: Federica Gigante