Doctor Maria Montessori believed that children pass through specific stages in their development when they are most able to learn specific skills. In Montessori education, these are called ‘sensitive periods’. According to Montessori Theory, the most important sensitive periods occur between birth and age six. Sensitive periods are commonly referred to as developmental milestones. During their first six years of life, children move through five main categories of sensitive periods, including: order, language, sensory skills, movement, and social skills. Each sensitive period lasts for as long as it is necessary for a child to complete a particular stage in their development. These periods of special sensitivity are only temporary and fade once the aim is accomplished. The Montessori Classroom supports these periods by providing children with hands-on activities that encourage repetition and problem solving to maximize learning during these windows of opportunity.