A cheder (חדר, lit. "room"; Yiddish pronunciation kheyder) is a traditional primary school teaching the basics of Judaism and the Hebrew language. Cheders were widely found in Europe before the end of the 18th century. Lessons took place in the house of the teacher, known as a melamed, whose wages were paid by the Jewish community or a group of parents. Normally, only boys would attend classes—girls were educated by their mothers in their homes. Where money was scarce and the community could not afford to maintain many teachers, boys of all ages would be taught in a single group. Although traditionally boys start learning the Hebrew alphabet the day they turned three, boys typically entered cheder school around the age of 5. After learning to read Hebrew, they would immediately begin studying the Torah, starting with the Book of Leviticus. They would usually start learning the Mishnah at around seven years of age and the Talmud (Mishnah, Gemara, and additional commentaries) as soon they had mastered the Mishnah. Reading out loud to each other and rote learning were the main techniques used to teach these complicated studies. At the age of 13 or 14, the end of a boy's education at the cheder would be marked by his bar mitzvah. Those who wanted to go on to become a rabbi or sofer had to continue their studies at an yeshiva, or Talmudic university. Famous European yeshivot were located at Worms, Fürth and Prague, which was considered to be among the best. After many Jews had fled to eastern Europe to escape medieval pogroms connected with the Crusades of that time, the intellectual centre of European Judaism moved with them and remained there for centuries. Towards the end of the 18th century, the cheder system became a target of critique by members of Jewish orthodoxy as well as by supporters of the more liberal Haskala (Jewish Enlightenment). Orthodox critics argued that teachers were not sufficiently qualified. At that time, cheder teachers were paid so badly that many would have to supplement their incomes with menial tasks.