"We left him after the battle of Prague in 1620. He remained in Prague until December, and then took up his winter quarters with a portion of the Duke of Bavaria's troops left in the extreme south of Bohemia. At this time a new and strange influence had come within his life. In that wonderfully productive winter spent with the Bavarian troops, while active operations were impossible, Descartes heard much of what was going on in the literary and scientific world. Amongst other things, he heard of that strange brotherhood of which we have so often read and yet of which we know so little—the Order of the Rosicrucians. They, it was said, taught a new wisdom, the hitherto undiscovered science. This was enough to excite Descartes' interest: Germany was thoroughly aroused; something had been discovered which was to be kept to the few initiated ones. The same Descartes who was in the habit of disdaining the work of others, began to think he had been precipitate in his judgments. Here was he searching for the Truth patiently and with difficulty, and there were men who declared the way had been opened to them. If these were simple imposters, then it was the duty of any honest man to expose their imposition; but if on the issue which to him was all-important, they had found any light, then, as he told his friend, how despicable would it be in him to disdain to be taught anything out of which he might obtain new knowledge. He made it his duty to discover a member of this learned body, in order to discuss the matter with him and subsequently settle his own conclusions. [footnote] The treatise which Descartes specially dedicates to the Order, is that which was written in 1619-20 and never published, the Polybii cosmopolitani Thesaurus mathematicus, which "sets forth the true means of solving this science, and in which it is demonstrated that nothing further can be supplied by the human mind"; "it is specially designed to relieve the pains of those who, entangled in the Gordian knot of the sciences, uselessly waste the oil of their genius." It is dedicated to all learned men, and more especially to the illustrious Brethren of the Rosicrucian Order in Germany. This may have been the treatise that in his journal he promises, if he can obtain sufficient books, and if it seems worthy of publication, on 23rd September 1620, though why the date should be thus fixed, we do not know. Probably when the time came he did not consider it "worthy," and now all is lost excepting the simple title."