Medieval Islamic navigation in the Atlantic Ocean extended over greater distances than is generally realized. Most was in a region bordered by the Iberian peninsula, the north-western coast of Africa, the Canaries Islands, the Azores, and Madiera, some of these islands being well known while others were little more than sailors' legends. This region of the ocean has sometimes been the so-called “Mediterranean Atlantic" as it was closely linked in technological, economic, and historical terms with the Mediterranean side of the Straits of Gibraltar. Most voyages by Muslim sailors in this “Mediterranean Atlantic" were undertaken for commercial, diplomatic or military reasons though some were a result of that intellectual curiosity, which characterized the golden age of medieval Islamic civilization. Roman vessels plied the coastal waters from the Straits of Gibraltar and the Iberian Peninsula to the English Channel and the British Isles. After the collapse of the western half of the Roman Empire, a maritime link appears to have survived between the Iberia peninsula and the Celtic western fringes of Brittany, the British Isles, and Ireland during the Visigothic period, before the Arab-Islamic conquest of al-Andalus but most particularly in the 7th century AD.' This may have survived into the Arab-Islamic period since it is clear that Britain remained the main source of tin for al-Andalus well into the 9^th century AD. Furthermore, it is worth noting that the famous terror stories about the Atlantic, or Sea of Darkness as it was widely known in the Islamic world, all seem to stem from the Middle East.³ None seem to have originated amongst the Arabized people of Morocco or al-Andalus.