of Ptolemy that had ever been of the judgment of Copernicus, and had left that to embrace this of Aristotle," he began to realize how strong must be the reasons that thus drew men away from beliefs "imbibed with their milk." [185] We can divine how slow would be the progress of a doctrine which could only thus begin to find its way into one of the most gifted scientific minds of the modern world. It was only a minority of the élite of the intellectual life who could receive it, even after the lapse of a hundred years. The doctrine of the earth's two-fold motion, as we have seen, had actually been taught in the fifteenth century by Nicolaus of Cusa (1401-1464), who, instead of being prosecuted, was made a cardinal, so little was the question then considered (Ueberweg, ii, 23-24). See above, vol. i, p. 368, as to Pulci. Only very slowly did the work even of Copernicus make its impression. Green (Short History, ed. 1881, p. 297) makes first the mistake of stating that it influenced thought in the fifteenth century, and then the further mistake of saying that it was brought home to the general intelligence by Galileo and Kepler in the later years of the sixteenth century (id. p. 412). Galileo's European notoriety dates from 1616; his Dialogues of the Two Systems of the World appeared only in 1632; and his Dialogues of the New Sciences in 1638. Kepler's indecisive Mysterium Cosmographicum appeared only in 1597; his treatise on the motions of the planet Mars not till 1609.