During the early centuries of Christianity, education focused on interests of the church. Monasteries were centers of learning until the Crusades led to the establishment of schools and universities. Early Christian schools taught adults and later children about the new faith, adding reading and writing. Figures like Clement of Alexandria, Origen, and Basil the Great emphasized connecting faith and knowledge, investigating ideas independently, using scripture as a textbook, and good habits being taught from a young age. Chrysostom believed teachers should lower themselves to students' level to elevate them and that religious instruction was essential to schoolwork.