Maria Montessori opened the first Montessori school in 1907 in an impoverished region of Rome. She named her school Casa de Bambini. In her work, she observed that the children (ages three to seven) enjoyed responding to sensorial input. They loved puzzles, gaining mathematical and cognitive skills through hours of play.

When given the opportunity to teach themselves, they thrived. Maria also noticed that, when playing, children focused on processes rather than specific results. Within a few years, Montessori schools opened throughout Western Europe. In America, Montessori made its debut in 1911.