Abstract: (ProQuest: ... denotes non-USASCII text omitted.)(ProQuest: ... denotes formulae omitted.)ONLY in recent years have the interrelationships of Babylonian, Greek, and Indian astronomy and astrology become a subject which can be studied meaningfully. This development is due to several factors: our greatly increased understanding of cuneiform material made possible by the scholarship of Professor O. Neugebauer; 1 the discovery of Babylonian parameters and techniques not only in the standard Greek astronomical texts,2 but in papyri and astrological treatises as well; and the finding of Mesopotamian material in Sanskrit works and in the traditions of South India. Unfortunately, a lack of familiarity with the Sanskrit sources and a failure to consider the transmission of scientific ideas in the context of a broad historical perspective have recently led one scholar to the erroneous conclusion that Sasanian Iran played a crucial role in the introduction of Greek and Babylonian astronomy and astrology to India and in the development of Indian planetary theory.4 It is my purpose in this paper to survey briefly the influence of foreign ideas on Indian gayakas so as to make clear the creative use they made of their borrowings in devising the yuga-system of astronomy; and then to examine the character of Sasanian astronomy and astrology, pointing out their almost complete lack of originality.The earliest Indian texts which are known - the Vedas, the Brâhmaijas, and the Upanicads - are seldom concerned with any but the most obvious of astronomical phenomena; and when they are so concerned, they speak with an obscurity of language and thought that renders impossible an adequate exposition of the notions regarding celestial matters to which their authors subscribed. One may point to the statement that the year consists of 360 days as a possible trace of Babylonian influence in the Kgveda,4 but there is little else which lends itself to a similar interpretation. It has often been proposed, of course, that the list of the twenty-eight naksatras which is given for the first time at the beginning of the last millennium before Christ in the Atharvaveda and in various Brâhmanas is borrowed from Mesopotamia.8 But no cuneiform tablet yet deciphered presents a parallel; the hypothesis cannot be accepted in the total absence of corroborative evidence.However, the naksatras are useful in the tracing of Indian influence on other cultures. The oldest lists0 associate each constellation with a presiding deity who is to be suitably propitiated at the appointed times. It became important to perform certain sacrifices only under the benign influence of particularly auspicious naksatras.7 The roster of activities for which each was considered auspicious or not was rapidly expanded,6 and, in particular, the naksatras came to be closely connected with the twelve or sixteen samskâras or purificatory rites. Thereby they gave rise to the most substantial part of muhurtasâstra, or Indian catarrhic astrology,® traces of which are to be found in Arabic, Byzantine, and medieval Latin texts.10 The Indians also combined the twenty-eight naksatras with the Babylonian arts of brontology and seismology 11 in a form which, for some unknown reason, became immensely popular among the followers of Buddha.'2 Their works spread these superstitions throughout Central Asia and the Far East.18The relative seclusion from the West which the Aryans had enjoyed in northern India for centuries alter their invasions was broken shortly before 51.3 b. c., when Darius the Great conquered the Indus Valley. In the ensuing six centuries, save for a century and a half of security under the Mauryan emperors, North India was subjected to the successive incursions of the Greeks, the eakas, the Pah lavas, and the Kuyânas. An important aspect of this turbulent period was the opportunity it afforded of contact between the intellectuals of the West and India. This opportunity was not missed. …