Throughout the sixteenth century, the calculations and theories of the ancient Greek and Egyptian mathematicians and astronomers served as the basis of cosmology, even as new discoveries undermined time-honored assumptions. Rather than acknowledge that a true scientific revolution was at hand, cosmologists responded to the challenge by trying to modify or bend classical schemes, especially the system codified by Claudius Ptolemy, the Greco-Egyptian astronomer and mathematician who lived in the second century A.D.
