The division of the Roman Empire from the late third century onward into an essentially Greek-speaking eastern part and a Latin-speaking western part had a momentous consequence for intellectual life and therefore for the history of science and natural philosophy. With the passage of time, knowledge of the Greek language in the Western empire became relatively rare. Because Greek had been the language of science, this meant that Greek science was essentially unavailable to those whose sole language was Latin. To become accessible to the Latin-speaking West, a Greek scientific treatise had to be translated into Latin. Few treatises were. Apart from a small number of Hippocratic medical treatises and the few translations made by the likes of Chalcidius and Boethius, almost no significant works of Greek science were translated into Latin. During the ninth and tenth centuries, when the Arabs were translating a large portion of Greek science into Arabic and also adding to this legacy, and during the period when Greek science continued to be read and studied in the Greek-speaking Byzantine Empire, the West had before it only the rudimentary science of the Latin encyclopedists already described in chapter 1. By a.d. 500, knowledge of Greek had become rare and knowledge of the exact sciences even rarer. Except for occasional translations, which sometimes failed to circulate or perished completely, little was added to the now dominant encyclopedic tradition.