Complex sentence: All boys who were between the ages of ten and twenty years old would attend one of the two schools: the Telpochcalli or the neighborhood school for commoners, and the Calmecac which was the exclusive school for nobles.
Split into simpler sentences: All boys who were between the ages of ten and twenty years old would attend one of the two schools. These two schools were broken into the Telpochcalli or the neighborhood school for commoners, and the Calmecac which was the exclusive school for nobles.