For during the year that elapsed before he left Swabia (and whilst he sojourned at Neuburg and Ulm), and amidst his geometrical studies, he would fain have gathered some knowledge of the mystical wisdom attributed to the Rosicrucians; but the Invisibles, as they called themselves, kept their secret.
At Rennes Descartes found little to interest him; and, after he had visited the maternal estate of which his father now put him in possession, he went to Paris, where he found the Rosicrucians the topic of the hour, and heard himself credited with partnership in their secrets.
In 1781 Frederick William, then prince of Prussia, inclined, like many sensual natures, to mysticism, had joined the Rosicrucians, and had fallen under the influence of Johann Christof Wollner (1732-1800), and by him the royal policy was inspired.
What is known as the Society of Rosicrucians (Rosenkreuzer) was really a number of isolated individuals who early in the 17th century held certain views in common (which apparently was their only bond of union); for of a society holding meetings, and having officers, there is no trace.
So far as the numerous works are concerned it is evident that the writers who posed as Rosicrucians were moral and religious reformers, and utilized the technicalities of chemistry (alchemy), and the sciences.
Others, like John Heydon, admitted they were not Rosicrucians, but under attractive and suggestive titles to their works sought to make Hermeticism and other curious studies more useful and popular, and succeeded, for a time at least.
The curious legend, in which the fabulous origin of the so-called society was enshrined (that a certain Christian Rosenkreuz had discovered the secret wisdom of the East on a pilgrimage in the 15th century), was so improbable, though ingenious, that the genesis of the Rosicrucians was generally overlooked or ignored, but the worthy objects of the fratres were soon discovered and supported by several able men; the result being a mass of literature on the subject, which absorbs some 80 pages of Gardner's Catalogue Raisonne of Works on the Occult Sciences (London, 1903).
The Rosicrucians, their Rites and Mysteries, by Hargrave Jennings (three editions, 1870-87); The Real History of the Rosicrucians, founded on their own Manifestoes and on Facts and Documents collected from the Writings of Initiated Brethren, by A.