[MUSIC] >> The story of world cycles in Islam is further complicated by the fact that it was frequently coupled with other shorter cycles of history allegedly determined by the return into conjunction of two planets, and especially the two farthest removed planets of the system, Jupiter and Saturn whose periods of revolution are about 12 and 30 years respectively. Taking up a theory originally developed in Sassanid Persia, Muslim astrologers attached great importance to three particular types of Jupiter-Saturn conjunctions. These can be determined by taking into account the zodiac signs and more specifically what astrologers define as the triplicities of the zodiac. It is not necessary to enter into the details of this theory. What matters for us here is to retain that the three types of conjunctions determined in this way correspond to periods of 20 years for the small conjunction type, 240 years for the middle conjunction type, and 960 years for the grand conjunction type. It was believed that each type determined a specific change in the affairs of the world. The replacement of one sovereign by another after 20 years, the replacement of one dynasty by another after 240 years, and the replacement of religion by another after 960 years. In various milieus of the Arab Muslim world it became quite common to use these elements to construct a highly developed form of history of the world divided into different cycles of prophethood. This was most noticeably the case in branches of Islam such as Ismailism, which were clearly on the fringe of mainstream orthodoxy. Turning to the scholars of the Latin middle ages, we observe how deeply they were inspired in this as in so many other fields by predecessors in the Arab Muslim world. In particular, the 12th and 13th centuries in Europe showed such a marked proclivity for astrological predictions and speculations of all kinds that those times have often been described as another great period of conjunctionsim. Indeed, believing in these cycles and in the effects that they were supposed to produce on the earth and its inhabitants was the rule. And so we find that the doctrine of planetary conjunctions was thoroughly endorsed even by champions of Christianity, such as Robert Grossteste, Albert the Great, and Roger Bacon. Now, it is true that a quite remarkable alignment of the planets did take place during that period. This occurred on the 16th of September 1186 CE, when all the planets, and even the nodes of the moon were found together in the sign of Libra. What is most remarkable is that we have ample evidence from Latin, Byzantine, and Arabic literatures of the time, reporting that the phenomenon had been predicted several years in advance by certain astronomers and astrologers of Toledo. In an enigmatic letter to the Pope, they had warned against devastating winds and other calamities resulting from the conjunction. Since none of these calamities actually occurred, one is not surprised to find in later literature on this issue some very sarcastic commentaries on the power of astrology. But once again, it was from the Christian authorities of the period that an organized counter reaction to this atmosphere of sheer speculation and superstition was to come. On the 7th of March, 1277, Etienne Tempier, the Bishop of Paris, issued a list of 219 articles officially condemned by the Church. Article six of this long list of condemned doctrines is terse. It consists of just 21 Latin words, which may be translated as follows. That when all heavenly bodies have come back to the same point, which takes place every 36,000 years, the same effects now in operation will come back. But it took a lot for Tempier's condemnation in which one may observe the persistence of the amalgamation discussed above to succeed in deterring people from believing in the effects of the great year. For many more generations, the doctrine remained extremely popular across Europe in spite of very stringent attacks from its opponents. One such opponent was Nicole Oresme. He undertook, in his own words, to attack philosophers with philosophy and mathematicians with mathematics and to demonstrate that the perfect conjunction of the planets was made an impossibility by the very incommensurability of their periods of revolution. And yet it was not before the renaissance that the great year doctrine gave it's last sigh. Looking back at this epoch of great discoveries, we may assume that the theory died a natural death. Obviously, it had by then fallen largely out of fashion since it could no longer find any place in the new heliocentric models of the universe. [MUSIC]