In 1988, by studying a scrap of Greek papyrus, Neugebauer discovered the most important single piece of evidence to date for the extensive transmission of Babylonian astronomy to the Greeks and for the continuing use of Babylonian methods for 400 years even after Ptolemy wrote the Almagest. His last paper, "From Assyriology to Renaissance Art", published in 1989, detailed the history of a single astronomical parameter, the mean length of the synodic month, from cuneiform tablets, to the papyrus fragment just mentioned, to the Jewish calendar, to an early 15th-century book of hours.