Light in the Cathedrals

_"The Sun in the Church" by J. L. Heilbron, in The Sciences (Sept.–Oct. 1999), New York Academy of Sciences, Two E. 63rd St., New York, N.Y. 10021._

After condemning Galileo in 1633 for adhering to the heretical notion that the Earth moved about the sun, the Roman Catholic Church, many historians believe, made Copernican astronomy a forbidden topic among faithful Catholics for the next two centuries. "But nothing could be further from the truth," asserts Heilbron, a historian at the University of California, Berkeley, and a senior research fellow at the University of Oxford.

"Beginning with the recovery of ancient learning in the 12th century and continuing through the Copernican upheavals and on even into the Enlightenment," he writes, "the Roman Catholic Church gave more financial and social support to the study of astronomy—Copernican and otherwise—than did any other institution." The reason for these centuries of lavish backing was the church’s pressing need to establish well in advance when Easter (which was to be celebrated on the first Sunday after the first full moon after the vernal equinox) would fall in a particular year—no easy task, given the state of astronomical knowledge of the time.