In the second place, the influence of Comenius was in formulating the general theory of education. In this respect, he is the forerunner of Rousseau, Pestalozzi, Fröbel, etc., and is the first to formulate that idea of "education according to nature" so influential during the latter part of the eighteenth and early part of the nineteenth century. The influence of Comenius on educational thought is comparable with that of his contemporaries, Bacon and Descartes, on science and philosophy. In fact, he was largely influenced by the thought of these two; and his importance is largely due to the fact that he first applied or attempted to apply in a systematic manner the principles of thought and of investigation, newly formulated by those philosophers, to the organization of education in all its aspects. The summary of this attempt is given in the "Didactica Magna", completed about 1631, though not published until several years later.