John Ashenden, who flourished between the years 1336and 1365, was a fellow of Merton College,Oxford, and an astrologer. In the later Middle Ages the science of the stars, or 'scientia astrorum', comprised both astronomy and astrology. Merton College is well known for the school of natural philosophy which prospered there in the first half of the fourteenth century. At the same time, a group of Merton fellows and their acquaintances specialized in the 'scientia astrorum'. Ashenden's writings are illustrative of the scholarship of this Merton circle. The circulation and copying of astronomical and astrological texts played a major part in their studies. Ashenden compiled a large 'Summa' of astrological theory from nearly one hundred sources. He also made predictions on the basis of reputed influences of eclipses and planetary conjunctions. Coincidental events, which appeared to follow what he had predicted, greatly encouraged him. He composed his predictions out of academic interest rather than for personal gain. His writings continued to be read for 400 years; yet by the Age of Enlightenment his learning had lost its value. Ashenden''s scholarship was indicative of the weaknesses of medieval scientific enquiry--it was mostly qualitative rather than quantitative; and assertions were never put to real experimental tests. Astrology had as much to do with theology as it had with science. The questions of determinism, natural causation,and numerological prophecy excited Oxford theologians. On these issues Ashenden stood on an orthodox middle-ground.