Maria Montessori was an advocate of early childhood education and founder of Montessori schools. She lived during a time of limited educational opportunities for women through which she broke and of which she took advantage in the late nineteenth and early twentieth centuries. Italian peasants migrated to larger cities like Milan and Rome to live in poor tenements that Maria saw as an educational opportunity to open Casa dei Bambini, or Children's House. Maria Montessori was born in Chiaravalle, Italy and lived from 1870-1952. Maria attended primary school in Rome but a technical secondary school. Subsequently she studied engineering but changed to become a pediatric physician at age 26, and practiced medicine for ten years. She opened her first school in 1907, with 50 children from 3 to 7 years old. Montessori's ideas were based on science, observations of children and her own research to develop Montessori methods. She believed children possess psychic power at birth to enable their inner self-teacher. Montessori schools total 6,000 in the United States promoting early childhood stimulation, sensitive periods of development, multifaceted learning and community involvement.