The Fast of Catechumens is a period of fasting established by St. Gregory the Illuminator, according to the tradition of the Armenian Church. After St Gregory the Illuminator was released from Khor Virap, he urged King Trdat (Tiridates III), the Armenian nobility, and the entire people to repent and fast for five days before receiving baptism.
It is commonly believed that this is how the Fast of Catechumens (Առաջավորաց պահք), also known as the First Fast of the Armenian Apostolic Church, was instituted. This explains its name, as it is considered the first officially established fast of the Church. The Fast of Catechumens begins three weeks before the Great Lent, starting on the Monday preceding the Feast of St. Sarkis.
The fifth and final day of the fast (Friday) is dedicated to the remembrance of St. Jonah the Prophet. His preaching and the repentance of Nineveh serve as powerful examples of great repentance and abstinence.
Following the fast, on Saturday, the Armenian Church celebrates the Feast of St. Sarkis.