During the 18th century, the Kingdom of Prussia was among the first countries in the world to introduce free and generally compulsory primary education, consisting of an eight-year course of basic education, "Volksschule". It provided not only the skills needed in an early industrialized world (reading, writing, and arithmetic) but also a strict education in ethics, duty, discipline and obedience. Children of affluent parents often went on to attend preparatory private schools for an additional four years, but the general population had virtually no access to secondary education and universities.