The Verona astrolabe

Islamic Spanish origins

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 scientific, design, construction and calligraphic characteristics.

She identified the object as Andalusian, and – from the style of the engraving, and the arrangement of the scales on the back – matched it to instruments made in Al-Andalus, the Muslim-ruled area of Spain, in the eleventh century.

One side of a plate is inscribed in Arabic “for the latitude of Cordoba, 38° 30',” لعزض قرطبة لح ل, while the other side “for the latitude of Toledo, 40°,” لعزض طليطلة م. Dr Gigante suggests that the astrolabe might have been made in Toledo at a time when it was a thriving centre of coexistence and cultural exchange between Muslim, Jews and Christians.

The astrolabe features Muslim prayer lines and prayer names, arranged to ensure that its original intended users kept to time to perform their daily prayers.

Translated into English, the signature inscribed on the astrolabe reads “for Isḥāq [...]/the work of Yūnus.” This was engraved sometime 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, a detail that suggests that the object was at a certain point circulating within a Sephardi Jewish community in Spain, where Arabic was the spoken language.

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

Hebrew inscriptions

Hebrew inscriptions were added to the astrolabe by more than one hand. One set of additions are carved deeply and neatly, while a different set of translations are very light, uneven, and show an insecure hand.

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

Unusually, one of the Hebrew additions, engraved neatly above the Arabic marking for latitude 35°, reads “34 and a half” rather than “34 ½”, which suggests that the engraver was not an astronomer or astrolabe maker.

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

Dr Gigante points out that these translations reflect the recommendations prescribed by the Spanish Jewish polymath Abraham Ibn Ezra (1089–1167) in the earliest surviving treatise on the astrolabe in the Hebrew language written in 1146 in Verona, exactly where the astrolabe is found today.

 Jewish Verona

Twelfth-century Verona hosted one of the longest-standing and most important Jewish communities in Italy. Ibn Ezra’s treatise assumes pre-existing knowledge of the astrolabe among the Verona Jewish community, showing that the instrument must already have been popular.

Ibn Ezra’s description has a lot in common with the ‘Verona astrolabe’ which would have been in circulation by the time Ibn Ezra was in Verona. He warned his readers that an instrument must be checked before use to verify the accuracy of the values to be calculated.

Dr Gigante suggests that the person who added the Hebrew inscriptions might have been following such recommendations.