There are four stages to the initiation process. The first stage is inquiry. That stage has no definite time frame. The amount of time is up to the inquirer.
The next stage is catechumenate. That takes at least one full liturgical year. It could take longer if the catechumen was not ready to move on the the third stage at the end of the year. The exact length cannot be determined ahead of time.
The third stage is enlightenment. This period coincides with Lent and lasts about 40 days.
The final stage is post-baptismal catechesis. That lasts for an intense 50-day period (Easter to Pentecost) and then a less intense period until the first anniversary of baptism.
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