The details of the fast, as they were prior to the tenth century, are as follows:
Some Eastern Rites Catholics Black Fast on Fridays during Lent, and especially on Good Friday. The Black Fast is still observed by the Eastern Orthodox on Wednesdays and Fridays and during the 40 days of Lent and three other fasting periods of the year.
St Basil, St Ambrose, St John Chrysostom and Pope St Gregory I have offered unequivocal testimony concerning the benefits of the Black Fast. The keynote of their teaching is summed up by St Bernard of Clairvaux when he says, "hitherto we have fasted only until None [3 pm] whereas, now kings and princes, clergy and laity, rich and poor will fast until evening". In the tenth century, the custom of taking the only meal of the day at three o'clock was introduced. In the fourteenth century, the hour of taking this meal was changed to noon-day. Shortly afterwards, the practice of taking a snack in the evening began to gain ground. Finally, the custom of taking some bread and coffee in the morning was introduced in the early part of the nineteenth century. During the past century, owing to ever changing circumstances of time and place, the Church has gradually relaxed the severity of all penitential requirements, so that now little more than a vestige of the former rigour remains.