 She saw different characteristics, learning modes, and developmental imperatives active in each of these planes, and called for educational approaches specific to each period.Over the course of her lifetime, Montessori developed pedagogical methods and materials for the first two planes, from birth to age twelve, and wrote and lectured about the third and fourth planes.Maria created over 4,000 Montessori classrooms across the world and her books were translated into many different languages for the training of new educators.