The document outlines the history and development of the catechumenate, a process for preparing converts for baptism, from the 3rd century to modern times. It notes that the catechumenate began taking shape in the 3rd century following Jesus' command to make disciples. It expanded in the 4th-5th centuries as Constantine legalized Christianity, and the concept of original sin developed. Elements of catechumenate were later used in religious formation, and it began being revived in the 12th-16th centuries in reaction against mass baptisms. The catechumenate was further developed by Vatican II in the 1960s and the Rite of Christian Initiation of Adults between 1972-1988.