Until the turn of the millennium the astrolabe was something of a mystery to western Christian scholars. But during his time at Reichenau, Hermann managed to obtain an incomplete manuscript partially describing its workings. This document somehow made its way to his little island from the caliphate of Córdoba, probably via the monastery of Santa Maria de Ripoll, about 100 kilometers north of Barcelona. It may have been written by Gerbert of Aurillac, the French scholar who became Pope Sylvester II. Whatever the case, it contained scientific intelligence that was well known in the Islamic world
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