Has the Lenten season always been 40 days long? Were the apostles actually the ones responsible for establishing it? Lent, as it’s known today took many centuries to develop.
In the first few centuries of the Church, Christians were frequently persecuted and it was hard for the bishops of the Church to create an embracing liturgical calendar. Generally, the local church was entrusted to the bishops and it was up to them to lead the Christian people in the worship of God. And this resulted in an early difference in how Christians celebrated Lent.
During the 2nd century, St. Irenaeus wrote a letter to the pope at that time about the variety of fasts before Easter.
For the controversy does not only concern the day [of Easter], but also it concerns the very manner of the fast. Some thought that they should fast for one day, others for two days. Moreover, some count their day as it consists of forty hours day and night. The early Christians agreed that a fast should go before the feast of Easter, but a duration of 40 days was not set in stone.
Scholars at the same time, have come to realize that some Christians in the Egyptian desert held a Post-Theophany fast for 40 days. The feast of the Theophany was done in the memory of the baptism of Jesus and was traditionally held on January 6. In that case, these Christians started a fast on the day after the Theophany so as to imitate Jesus, who went into the wilderness to fast for 40 days immediately after his own baptism.
Though their fast did not end on Easter, it did end with a baptismal ceremony, introducing new members into the Christian faith. It was believed that the tradition of the Post-Theophany fast was later merged with other traditions to create the Lenten season as we know it today.
Though, It wasn’t until after the Council of Nicea in the year 325 that Lent was universally established as a 40-day fast. Legalization of Christianity gave way for a more public celebration of fasting and the bishops were finally able to start the process of uniting under the Bishop of Rome in all things, including liturgical disciplines.
As Lent has changed since the beginning of the Church, the roots of Lent has also gone deep and the extensive fast for 40 days has ancient origins.