The importance of this for the history of religions can hardly be exaggerated. Greek was spoken everywhere throughout Asia, and for the first time in the world’s history the inhabitants of the civilized part of the earth had a common tongue in which they could communicate their ideas to each other. No doubt the language spoken by the offspring of Greek colonists and their native spouses was not the tongue of Sophocles or of Demosthenes any more than it was “the strong-winged music of Homer”; but it was a better medium for the transmission of metaphysical theories than the founder of any world-religion has ever had at his disposal before or since. The missionaries whom modern nations send into the distant parts of the earth for the propagation of the Christian faith find one of their worst difficulties in the impossibility of rendering its doctrines into the languages of peoples at another stage of culture from themselves; but no such barrier between teacher and taught existed in the empire created by Alexander’s genius. The result of this possibility of intercommunication of ideas was at once apparent. Anxious to show that they too had a pedigree, the older nations of the world seized the opportunity to inform their new masters of their own history and traditions; and, as all history was in those days sacred history, they thus introduced to the Greeks their gods and their beliefs as to the divine governance of the world. The sacred books of the Chaldeans, of the Egyptians, of the Jews, and no doubt of many other peoples whose records are now lost to us, were translated into Greek; and thus the science of the history of religions was born. Writers like Diodorus Siculus and Plutarch are still our chief guides for the religions of the earliest populated parts of the ancient world; but how could these compilers have handed down to us the traditions they have preserved save for writers like Berossus, Manetho, and Philo of Byblus, who themselves wrote in Greek? Plutarch tells us that when he spent a year in Rome during the reign of Trajan, he did not find it necessary to learn Latin, his native tongue being apparently understood by everybody. One may wonder how much of the sayings and doings of the Founder of Christianity would have come down to us, had they not been first recorded in the κοινή or _lingua franca_ of the whole East[51].