The third aspect of his educational influence was that on the subject matter and method of education, exerted through a series of textbooks of an entirely new nature. The first-published of these was the "Janua Linguarum Reserata" (The Gate of Tongues Unlocked), issued in 1631. This was followed later by a more elementary text, the "Vestibulum", and a more advanced one, the "Atrium", and other texts. In 1658 the "Orbis Pictus" was published, probably the most renowned and most widely circulated of school textbooks. It was also the first successful application of illustrations to the work of teaching, though not, as often stated, the first illustrated book for children.