For Aztec children, education began in the home. The girls would learn domestic chores, and boys learned their fathers' trades. Once they were trained to deal with hardship, at the ages of 12 to 15, all children were required to attend a school or house of song, where they learned ceremonial songs and the cosmology of their people. For most girls, formal education ended at age 15, but from 15 to 20 years of age, the boys had to attend another school known as telpochcalli, for military training. Sons born to nobility would attend a separate school (calmécac), too, where they studied the humanities as well.