The Pestalozzian movement of the 19th century represented the ideas of Swiss educator Johann Heinrich Pestalozzi (1746-1827) and was based on the premise that learning occurs best in an emotionally-secure environment where knowledge is acquired by sense perception. Influenced by Jean-Jacques Rousseau, Pestalozzi introduced psychology into education and was the first to systematize the science of teaching. Though known for the object lesson, he also influenced the transformation of elementary schools and planted seeds for teacher licensure.