In the Catholic Church, CCD stands for the Confraternity of Christian Doctrine. In 1562, an organization founded CCD in Rome as a focus on religious instruction. In modern day usage, CCD is a religious education program provided to children by the Catholic church.
Earliest forms of Christian education focused on memorization of the Lord's Prayer and Apostle's Creed. Over time, this expanded to include the sacraments and the 10 Commandments. In Milan, Italy 1536, Abbate Castellino da Castello established Sunday schools, and in 1562, a central organization called the Confraternity of Christian doctrine oversaw the religious education of the population.
In 1908, Marion Gurney founded the Sister of Our Lady of Christian Doctrine to provide religious education to the increasing Catholic immigrant population in the United States.