Astrolabe, Gift Of The Arabs
The astrolabe was an instrument of critical importance in [eleventh-century C.E.] Europe’s intellectual advance. It permitted all sorts of astronomical observations to be made with hitherto unmatched accuracy; it made possible rapid and accurate terrestrial measurements, for example of height and distance; it could be turned to navigational use and it could serve as a clock. The astrolabe was invented in antiquity, but the Arabs were the first to grasp its potential and elaborate its design. Knowledge of it was quickly diffused throughout the Islamic world….
— Richard Fletcher, The Quest for El Cid, p. 53