The catechumenate, an old institution, older in most regions than the mysteries themselves, suggested and rendered feasible such wholesale theft, especially in an age in which the sacerdotal class wished to be pre-eminent, and left nothing undone to enhance in the eyes of the multitude the importance and solemnity of rites which it was their prerogative to administer.
The long probation called "abstinence" which led up to it is a survival of the primitive catechumenate with its scrutinies.
About the year 300, those desirous of being baptized were (a) admitted to the catechumenate, giving in their names to the bishop. (b) They were subjected to a scrutiny and prepared, as to-day in the western churches the young are prepared for confirmation.
In some churches they had worn cowls during the catechumenate, in sign of repentance of their sins.
These two rites really begin the catechumenate or period of instruction in the faith and discipline of the church.
Modern scholars, however, for the most part, deny that there is sufficient basis to justify this elaborate classification, and think that its advocates have confused the catechumenate with the system of penance.
There can be little doubt that this conception of the "Holy Secret" came into the Church originally from the Greek mysteries, and that much of the ceremonial connected with the catechumenate and baptism was derived from the same source.