The first pre-schools in Denmark were established in the 1820s by a private initiative intended to instruct the children of working families, where both parents worked outside the home. During the period between 1850 and 1900, private educational institutions appeared that were open only on a part-time basis. These institutions had pedagogical objectives unlike those of the previous schools that were mostly mere retention centres for children of working parents, and were aimed at the children of the more privileged classes.