'Fake' astrolabe in Italian museum is rare 11th-century Islamic-Jewish 'smartphone'

Multi-use instrument adorned with Hebrew and Arabic inscriptions discovered after art expert's chance encounter

The Verona astrolabe, which has inscriptions in Hebrew and Arabic, is thought to have been taken across Europe and North Africa. Photo: Federica Gigante

An "incredibly rare" 11th-century instrument used by Muslims to determine where to pray and to calculate the dates for the start of Ramadan and Eid has been identified by an art expert.

The astrolabe with Arabic and Hebrew inscriptions was discovered at an Italian museum where its historical importance had been overlooked for decades.

The astronomical artefact is believed to have originated in Andalusia in Spain, and was modified multiple times as it was taken across Europe and North Africa before eventually arriving in Italy centuries ago.

Dr Federica Gigante, from Cambridge University’s History Faculty, discovered the item while viewing a newly uploaded image on the website of the Fondazione Museo Miniscalchi-Erizzo in Verona.

The discovery is a powerful record of scientific exchange between Christians, Muslims and Jews over hundreds of years, she says.

Astrolabes, which were first used in ancient Greece, were extensively developed in the Islamic world and became a key astronomical instrument during the Middle Ages. Their size varies but they are typically between six and 18 inches in diameter.

Its multitude of uses, which included navigation, telling the time and determining the length of the day and night, made it like the smartphone of its day.

The astrolabe is thought to have eventually made its way into the collection of the Veronese nobleman Ludovico Moscardo (1611–81) before passing by marriage to the Miniscalchi family.

In 1990, the family founded the Fondazione Museo Miniscalchi-Erizzo to preserve the collections.

“This object is Islamic, Jewish and European – they can’t be separated,” Dr Gigante said.

Some in the museum believed it was fake but it is now considered the single most important object in their collection, Dr Gigante added.

“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.”

Dr Gigante, an expert on Islamic astrolabes and previously a curator of Islamic scientific instruments, dated and located the creation of the Verona astrolabe by analysing key design and calligraphic characteristics.

The Verona astrolabe example features Muslim prayer lines and prayer names, arranged to ensure that its original users performed their daily prayers on time.

The signature inscribed on the astrolabe reads “for Isḥāq [...]/the work of Yūnus”. This was engraved some time after the astrolabe was made, probably for a later owner.

The two names, Isḥāq and Yūnus, that is Isaac and Jonah in English, could be Jewish names written in the Arabic script.

Dr. Gigante identified the object as Andalusian, and matched it to instruments made in Al-Andalus, the Muslim-ruled area of Spain, in the 11th century.

It is believed the item was at one stage circulating among the Sephardic Jewish community in Spain, where Arabic was the spoken language.

A second, added plate is inscribed for typical North African latitudes, suggesting that at another point of the object’s life it was perhaps used in Morocco or Egypt.

At least three separate users felt the need to add translations and corrections to the object, two using Hebrew and one using a Western language, Dr Gigante said.

“These Hebrew additions and translations suggest that at a certain point the object left Spain or North Africa and circulated among the Jewish diaspora community in Italy, where Arabic was not understood, and Hebrew was used instead.”

Other Hebrew inscriptions are translations of the Arabic names for the Scorpio, Sagittarius, Capricorn, Aquarius, Pisces, and Aries astrological signs.